Search

This study investigated the effect of subcutaneously administered oxyntomodulin on body weight in healthy overweight and obese volunteers. Participants self-administered saline or oxyntomodulin subcutaneously in a randomized, double-blind, parallel-group protocol. Injections were self-administered for 4 weeks, three times daily, 30 min before each meal. The volunteers were asked to maintain their regular diet and level of physical exercise during the study period. Subjects' body weight, energy intake, and levels of adipose hormones were assessed at the start and end of the study. Body weight was reduced by 2.3 +/- 0.4 kg in the treatment group over the study period compared with 0.5 +/- 0.5 kg in the control group (P = 0.0106). On average, the treatment group had an additional 0.45-kg weight loss per week. The treatment group demonstrated a reduction in leptin and an increase in adiponectin. Energy intake by the treatment group was significantly reduced by 170 +/- 37 kcal (25 +/- 5%) at the initial study meal (P = 0.0007) and by 250 +/- 63 kcal (35 +/- 9%) at the final study meal (P = 0.0023), with no change in subjective food palatability. Oxyntomodulin treatment resulted in weight loss and a change in the levels of adipose hormones consistent with a loss of adipose tissue. The anorectic effect was maintained over the 4-week period. Oxyntomodulin represents a potential therapy for obesity. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to generate a map of local recurrences after neoadjuvant chemotherapy and radiation (total neoadjuvant therapy [TNT]) followed by surgical resection for pancreatic ductal adenocarcinoma (PDAC). Such recurrence patterns will serve to inform radiation treatment planning volumes that should be given in the neoadjuvant setting., Methods and Materials: Locoregional recurrences after TNT followed by surgery treated between 2009 and 2022 were radiologically identified. Recurrences were individually segmented using MIM software and complied in a single base scan. All contour compilations were used to create a threshold contour encompassing 80% of recurrences among all patients, head only, and body/tail only. The distance between organs at risk and the threshold contour were measured to design an optimal clinical target volume contour for patients treated with TNT. Recurrence patterns were also compared with existing adjuvant guidelines to assess coverage., Results: A database of 474 patients managed with TNT for PDAC was queried. While locoregional recurrences were rare in this cohort, we identified 80 patients with either isolated locoregional or simultaneous local and distant recurrences. Patients with diagnostic imaging at the time of recurrence were identified. The majority of recurrences were partially in the field of published contouring guidelines or volumetric expansions off of vessels, and volumetric coverage was low for all. Common areas of recurrence include the aorticodiaphragmatic junction, retropancreatic duodenal nodal basin, and the region to the right of the superior mesenteric artery. A novel set of proposed neoadjuvant contours was designed to cover the central-most 80% of recurrences., Conclusions: This is the largest collection of local/regional PDAC recurrences from a cohort of patients treated exclusively with TNT. Patterns of local/regional recurrence using TNT in PDAC vary significantly from those patients with PDAC treated with a surgery-first approach. Novel contouring guidelines presented in this study can help to ensure optimal coverage of high risk regions and avoid reliance on the current adjuvant guidelines to guide treatment planning., (Published by Elsevier Inc.)

Burnout, defined by the presence of emotional exhaustion, depersonalization, and decreased sense of personal accomplishment, impacts a significant portion of radiation oncologists. This has been exacerbated by the COVID-19 pandemic, is notably worse for women, and has been identified as an international concern. Key contributors to burnout within radiation oncology include inadequate clinical and administrative support, imbalanced personal and professional lives including time with family and for self-care, decreased job satisfaction secondary to increased electronic medical record and decreased patient time, unsupportive organizational culture, lack of transparency from leadership and inclusion in administrative decisions, emotionally intensive patient interactions, challenges within the radiation oncology workforce, financial security related to productivity-based compensation and increasing medical training-related debt, limited education on wellness, and fear of seeking mental health services due to stigma and potential negative impacts on the trajectory of one's career. Limited data exist to quantify the impacts of these factors on the overall levels of burnout within radiation oncology specifically, and additional efforts are needed to understand and address root causes of burnout within the field. Strategies should focus on improving the systems in which physicians work and providing the necessary skills and resources to thrive in high-stress, high-stakes work environments., (Copyright © 2023 American College of Radiology. All rights reserved.)

Background: Approximately 80% of patients with asthma and chronic obstructive pulmonary disease incorrectly use a metered-dose inhaler and, therefore, fail to obtain full benefit from their inhaler medication. Beclomethasone dipropionate (BDP) hydrofluoroalkane, an inhalation aerosol administered via a breath-actuated inhaler (BAI) has been designed to improve ease of use over press-and-breathe metered-dose inhalers by eliminating the need for hand-breath coordination. Objective: To present the mechanics of the BAI device, assess the minimum reliable inspiratory flow rate required to trigger an actuation, and evaluate if intended users can safely and effectively use the BDP BAI according to the instructions for use (IFU). Methods: Six random batches (three batches each of 40 μg and 80 μg) of 10 inhalers were evaluated for the minimum inspiratory flow rate required for actuation trigger. Each inhaler was tested for actuation at five flow rates: 12, 14, 16, 18, and 20 L/min. Simulated-use testing was conducted with 91 participants from six representative user groups in the United States to assess the use of a placebo-filled production-equivalent BDP BAI according to the IFU. Results: Across the 40-μg batches, 83% of the devices actuated at 16 L/min and 100% actuated at 18 and 20 L/min. For the 80-μg batches, 67% and 100% actuated at 18 L/min and 20 L/min, respectively. All the participants demonstrated successful use of the BDP BAI during the study session. Isolated safety-critical errors with the potential for no-dose delivery were recorded for 15 participants but were considered unrelated to the design of the IFU. Conclusion: The BDP BAI consistently triggered actuation at an airflow rate of 20 L/min and was successfully used based on guidance from the IFU only. This device provides an alternative for patients who find it difficult to use metered-dose inhaler devices correctly.

Introduction: Handheld spirometers for home use by patients allow longitudinal spirometry data to be collected daily and may overcome some of the limitations of in-clinic spirometry (long intervals between measurements, results can be affected by site-based coaching and patient's asthma status during a given visit)., Objectives: To determine the relationship between spirometry values measured by clinic-based and handheld spirometers during a clinical trial., Methods: A post hoc correlation analysis of data from a 6-week phase 3 study of beclomethasone dipropionate (BDP; delivered by breath-actuated inhaler: BAI) versus placebo in patients aged ≥12 years with persistent asthma. During the study, forced expiratory volume in 1 s (FEV 1 ) was assessed by both office-based spirometry at Weeks 2, 4 and 6, and daily by handheld spirometer as a secondary study endpoint., Results: There was a high correlation between FEV 1 values measured at home and in-clinic (overall correlation coefficient = 0.8393, R = 0.81921, 0.85927, 0.85369 and 0.83734 for BAI 320 μg/day, BAI 640 μg/day, BDP metered dose inhaler 320 μg/day and placebo treatment groups, respectively), with the scatterplot showing an upward trend for all treatment groups. Nearly all patients achieved home FEV 1 values close to clinic FEV 1 values, with very few outliers., Conclusions: Clinic-based and handheld spirometry demonstrated comparable treatment effects relative to placebo, suggesting that home spirometry could be used to help patients monitor their asthma severity. Daily measurement of FEV 1 provides more comprehensive data than can be achieved through clinic visits, and may lead to a new approach to clinical trial design., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Breath-actuated inhalers (BAIs) eliminate the need for hand-breath coordination required of pressurized metered-dose inhalers (MDIs). This pharmacokinetic study compared systemic exposure following beclomethasone dipropionate delivery through BAI versus MDI., Methods: This open-label, three-period crossover, single-dose study randomized healthy subjects aged 18-45 years (N = 72) to 1 of 6 treatment sequences containing beclomethasone dipropionate BAI 160 mcg (40 mcg/inhalation, 4 inhalations), beclomethasone dipropionate BAI 320 mcg (80 mcg/inhalation, 4 inhalations), and beclomethasone dipropionate MDI 320 mcg (80 mcg/inhalation, 4 inhalations). Blood samples were collected predose through 24 hours postdose for determination of plasma concentrations of beclomethasone-17-monopropionate (17-BMP), the active metabolite of beclomethasone dipropionate. The primary pharmacokinetic parameters were area under the plasma drug concentration-time curve (AUC) from time 0 (predose) until the last measurable drug concentration (AUC 0-t ) and maximum plasma drug concentration (C max ) for 17-BMP. Safety was assessed by adverse events, vital signs, clinical laboratory tests, and physical examinations., Results: Plasma concentrations of 17-BMP peaked at a median of 10 minutes after the last inhalation of all study treatments and remained measurable for at least 18 hours in most subjects. Mean elimination half-life was ∼4 hours. The AUC 0-t and C max for 17-BMP were 11% and 14% higher, respectively, when beclomethasone dipropionate 320 mcg was administered through BAI versus MDI, but the 90% confidence intervals of the geometric least squares mean BAI:MDI ratio for each parameter were fully contained within the bioequivalence boundaries of 0.80-1.25. Plasma concentrations of 17-BMP following beclomethasone dipropionate 160 mcg BAI were approximately half those with 320 mcg through BAI or MDI. All treatments were safe and generally well tolerated., Conclusions: Systemic availability of 17-BMP following administration of beclomethasone dipropionate was bioequivalent between BAI and MDI at the 320-mcg dose, and approximately dose proportional at the 160- and 320-mcg doses using the BAI.

Background: Breath-actuated inhalers (BAI) eliminate the need for the hand-breath coordination required with standard metered-dose inhalers (MDI)., Objective: To evaluate the efficacy and safety of beclomethasone dipropionate (BDP) administered via BAI., Methods: This 6-week, phase III, double-blind study included patients aged ≥12 years with persistent asthma. During the single-blind run-in, patients discontinued asthma medications and received twice-daily placebo BAI or MDI. At randomization, BAI patients received BDP BAI 320 μg/day, BDP BAI 640 μg/day, or placebo BAI, and MDI patients received BDP MDI 320 μg/day or placebo MDI. Assessments included standardized baseline-adjusted trough morning forced expiratory volume in 1 second (FEV1) area under the effect curve from 0 to 6 weeks (AUEC[0-6 wk]) (obtained by clinic-based spirometry; the primary end point), morning peak expiratory flow (PEF), trough daily morning FEV1 (obtained by handheld spirometry), withdrawals, and tolerability., Results: Of 425 patients randomized, most were white (81%) and female (61%). BDP BAI 320 and 640 μg/day significantly improved FEV1 AUEC(0-6 wk) versus placebo (p < 0.001). The BDP BAI treatment groups exhibited significantly improved morning PEF and daily morning FEV1 versus placebo (p < 0.001). Similar treatment effects were demonstrated for BDP MDI (p < 0.001). Fewer patients withdrew due to worsening asthma while taking BDP BAI 320 μg/day (n = 1), BDP BAI 640 μg/day (n = 0), and BDP MDI 320 μg/day (n = 1) versus placebo (n = 10). BDP BAI was well tolerated., Conclusion: BDP BAI demonstrated significant improvements in pulmonary function versus placebo, with results similar to BDP MDI. The safety profile of BDP BAI was comparable to BDP MDI, with no new safety signals.The study was registered on ClinicalTrials.gov (NCT02513160), www.clinicaltrials.gov.

Background: Breath-actuated inhalers (BAI) may simplify the delivery of inhaled medications compared with other devices., Objective: To evaluate the efficacy and safety of beclomethasone dipropionate BAI versus matching placebo in adolescent and adult patients with persistent asthma., Methods: This phase III, 12-week, double-blind study enrolled patients with asthma aged ≥12 years who were previously treated with a stable dose of inhaled corticosteroid or noncorticosteroid therapy. After a run-in period of 14 to 21 days, patients were randomly assigned in a 1:1:1 ratio to beclomethasone dipropionate BAI 80 or 160 micrograms/day (40 or 80 micrograms twice daily) or placebo BAI. The primary end point was the standardized baseline-adjusted trough morning forced expiratory volume in 1 second (FEV1) area under the effect curve from time 0 to 12 weeks (AUEC[0-12 weeks]). Secondary end points included peak expiratory flow, rescue medication use, asthma symptoms, and the time to withdrawal due to meeting predefined criteria for worsening asthma. Additional end points evaluated quality of life, instructions for use, and safety., Results: The full analysis and the safety sets included 270 and 273 patients, respectively. Patients who received beclomethasone dipropionate BAI 80 or 160 micrograms/day had significant improvements in FEV1 AUEC(0-12 weeks) versus placebo (p ≤ 0.001). Improvements in secondary end points were also apparent in patients who received beclomethasone dipropionate BAI 80 or 160 micrograms/day compared with placebo. Patients who received beclomethasone dipropionate BAI 80 or 160 micrograms/day had greater increases in Asthma Quality of Life Questionnaire scores versus placebo patients at week 12. Of 98 patients who participated in the instructions-for-use substudy, 87 (88.8%) used the inhaler successfully on their first attempt. Treatment was generally safe and well tolerated., Conclusion: Beclomethasone dipropionate BAI 80 and 160 micrograms/day were effective and well-accepted treatments in patients with asthma, with safety comparable to beclomethasone dipropionate delivered via a metered-dose inhaler.Clinical trial NCT02040779, www.clinicaltrials.gov.

Background: Breath-actuated inhalers (BAI) eliminate the need for hand-breath coordination and, therefore, simplify the delivery of inhaled medication., Objective: To evaluate the efficacy and safety of beclomethasone dipropionate BAI and metered-dose inhaler (MDI) versus placebo in pediatric patients ages 4-11 years with persistent asthma., Methods: In this double-blind, double-dummy, phase III study, 628 children with persistent asthma were randomly assigned (1:1:1:1:1) to twice-daily beclomethasone dipropionate (BAI 80 μg/day, BAI 160 μg/day, MDI 80 μg/day, or MDI 160 μg/day) or to placebo. Efficacy over 12 weeks was assessed by spirometry, peak expiratory flow (PEF) measurements and other clinical end points. The primary efficacy end point was the baseline-adjusted trough morning percent predicted forced expiratory volume in 1 second (PPFEV1) area under the effect curve from 0 to 12 weeks (AUEC[0-12 weeks])., Results: PPFEV1 AUEC(0-12 weeks) showed numerical improvements from baseline in the BAI 80 μg/day and BAI 160 μg/day groups and MDI 80 μg/day and MDI 160 μg/day groups; however, these improvements were not significant versus placebo for any group after hierarchical testing was applied. Consistent improvements were noted in the active treatment groups versus placebo for the weekly average trough morning and evening PEFs, and with BAI 80 μg/day versus placebo for rescue albuterol/salbutamol use and the total daily asthma symptom score. Most patients indicated that the BAI device was easy or very easy to use. Adverse events were comparable across the groups; the incidence of oral candidiasis ranged from 0.8 to 3.2%., Conclusions: Although the primary efficacy end point was not demonstrated, consistent improvements in PEF and other clinical end points were observed with beclomethasone dipropionate BAI, particularly at the 80 μg/day dose. These clinical benefits, combined with the need for better symptom control in children with asthma, supported the development of beclomethasone dipropionate BAI.

Purpose: Ir-192 is the predominant source for high-dose-rate (HDR) brachytherapy in United States markets. Co-60, with longer half-life and fewer source exchanges, has piloted abroad with comparable clinical dosimetry but increased shielding requirements. We sought to identify practitioner knowledge of Co-60 and establish acceptable willingness-to-pay (WTP) thresholds for additional shielding requirements for use in future cost-benefit analysis., Methods and Materials: A nationwide survey of U.S. radiation oncologists was conducted from June to July 2015, assessing knowledge of HDR sources, brachytherapy unit shielding, and factors that may influence source-selection decision-making. Self-identified decision makers in radiotherapy equipment purchase and acquisition were asked their WTP on shielding should a more cost-effective source become available., Results: Four hundred forty surveys were completed and included. Forty-four percent were ABS members. Twenty percent of respondents identified Co-60 as an HDR source. Respondents who identified Co-60 were significantly more likely to be ABS members, have attended a national brachytherapy conference, and be involved in brachytherapy selection. Sixty-six percent of self-identified decision makers stated that their facility would switch to a more cost-effective source than Ir-192, if available. Cost and experience were the most common reasons provided for not switching. The most common WTP value selected by respondents was <$25,000., Conclusions: A majority of respondents were unaware of Co-60 as a commercially available HDR source. This investigation was novel in directly assessing decision makers to establish WTP for shielding costs that source change to Co-60 may require. These results will be used to establish WTP threshold for future cost-benefit analysis., (Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.)

Background: Breath-actuated inhalers (BAI) have been developed to simplify the delivery of inhaled medication., Objective: To evaluate the safety and efficacy of beclomethasone dipropionate hydrofluoroalkane BAI and metered-dose inhaler (MDI) versus placebo in patients who previously used a mid- to high-dose inhaled corticosteroid or inhaled corticosteroid/long-acting beta agonist for persistent asthma., Methods: This phase III study included five treatment groups: placebo, and four beclomethasone dipropionate groups (BAI 320 μg/day, BAI 640 μg/day, MDI 320 μg/day, and MDI 640 μg/day). Efficacy over 12 weeks was assessed by spirometry, peak flow measurements, and other clinical end points. Safety was assessed by adverse events., Results: Baseline-adjusted trough morning forced expiratory volume in 1 second area under the effect curve from time 0 to 12 weeks (primary end point) was increased in the BAI 320 and BAI 640 μg/day groups and the MDI 640 μg/day group versus placebo (not significant). Clinically important improvements were noted in morning and evening peak expiratory flow and decreased rescue medications. More patients who received placebo than patients in active treatment groups withdrew due to meeting the stopping criteria for worsening asthma. Patients in the active treatment groups experienced a greater decrease in asthma symptoms than patients in the placebo group. Quality of life and Asthma Control Test scores improved in the active treatment groups compared with the placebo group (p ≤ 0.0074). The most common adverse events (>5% in any group) were oral candidiasis and upper respiratory tract infection., Conclusion: Clinical benefits for patients who used BAI 320 and 640 μg/day and MDI 640 μg/day were demonstrated. The safety profiles of BAI 320 and 640 μg/day were comparable with that of the MDI. These benefits and the continued need for better symptom control among patients with asthma support the continued development of this controller medication. ClinicalTrials.gov identifier NCT02031640.

Background: Intranasal corticosteroids are the mainstay of allergic rhinitis (AR) treatment. Their potential to suppress the hypothalamic-pituitary-adrenal axis should be evaluated, especially after long-term daily use in children., Objective: To evaluate the effects of treatment with non-aqueous beclomethasone dipropionate (BDP) nasal aerosol on hypothalamic-pituitary-adrenal axis function in children with perennial AR., Methods: In this double-blinded, placebo-controlled, parallel-group study, patients (6-11 years old) with perennial AR were randomized (2:1) to BDP nasal aerosol at 80 μg/day (n = 67) or placebo (n = 32). The primary end point was change from baseline in 24-hour serum cortisol (SC) weighted mean for BDP nasal aerosol and placebo after 6 weeks of treatment, which was analyzed in the per-protocol population., Results: The per-protocol population included 97 patients (BDP nasal aerosol, n = 66; placebo, n = 31). Baseline geometric mean SC weighted mean values were similar in the 80-μg/day BDP nasal aerosol and placebo groups (5.97 and 6.47 μg/dL, respectively). After 6 weeks' treatment, geometric mean values were 6.19 and 7.13 μg/dL, respectively, with no decrease from baseline in either group. Geometric mean SC ratio of BDP nasal aerosol at 80 μg/day to placebo was 0.91 (95% confidence interval 0.81-1.03), indicating predefined noninferiority. SC concentration-time profiles were similar for the placebo and 80-μg/day BDP nasal aerosol groups at baseline and week 6. BDP nasal aerosol at 80 μg/day was generally well tolerated., Conclusion: In pediatric patients with perennial AR, 24-hour SC profiles were comparable for BDP nasal aerosol and placebo, indicating that once-daily BDP nasal aerosol treatment did not significantly affect hypothalamic-pituitary-adrenal axis function., Trial Registration: ClinicalTrials.gov; NCT01697956., (Copyright © 2015 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Beclomethasone dipropionate (BDP) nasal aerosol (non-aqueous) is approved for management of seasonal and perennial allergic rhinitis (PAR) in adolescents and adults., Objective: To evaluate the efficacy and safety of BDP nasal aerosol at 80 μg/day in children with PAR., Methods: This 12-week, phase 3, double-blinded, placebo-controlled, parallel-group study randomized 547 children (4-11 years old) with PAR to once-daily BDP nasal aerosol at 80 μg/day or placebo. The primary end point was change from baseline in average morning and evening reflective total nasal symptom score (rTNSS) during the first 6 weeks of treatment in patients 6 to 11 years old. Changes from baseline in average morning and evening instantaneous TNSS (iTNSS) in children 6 to 11 years old and average rTNSS and iTNSS in children 4 to 11 years old were assessed during the first 6 weeks of treatment., Results: Improvements were significantly greater with BDP nasal aerosol than with placebo during the first 6 weeks of treatment in children 6 to 11 years old in average morning and evening rTNSS and iTNSS (mean treatment difference -0.66 [P = .002] and -0.58 [P = .004], respectively). Improvements in average morning and evening rTNSS and iTNSS also were significantly greater in patients 4 to 11 years receiving BDP nasal aerosol than with placebo during the first 6 weeks of treatment (P = .002 and P = .004, respectively). Similar improvements were seen during 12 weeks of treatment. The safety profile of BDP nasal aerosol was comparable to that of placebo., Conclusion: The BDP nasal aerosol at 80 μg/day in children 4 to 11 years old was well tolerated and effective in controlling nasal symptoms of PAR., Trial Registration: www.clinicaltrials.gov, identifier NCT01783548., (Copyright © 2015 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Objective: The hypothalamic control of energy balance is regulated by a complex network of neuropeptide-releasing neurons. Although the effect of these neuropeptides on individual aspects of energy homoeostasis has been studied, the coordinated response of these effects has not been comprehensively investigated. We have simultaneously monitored a number of metabolic parameters following intracerebroventricular (ICV) administration of 1 and 3 nmol of neuropeptides with established roles in the regulation of feeding, activity and metabolism. Ad libitum- fed rats received the orexigenic neuropeptides neuropeptide Y (NPY), agouti-related protein (AgRP), melanin-concentrating hormone (MCH) or orexin-A. Overnight-food-deprived rats received an ICV injection of the anorectic peptides alpha-melanocyte-stimulating hormone (MSH), corticotrophin-releasing factor (CRF) or neuromedin U (NMU)., Results: Our results reveal the temporal sequence of the effects of these neuropeptides on both energy intake and expenditure, highlighting key differences in their function as mediators of energy balance. NPY and AgRP increased feeding and decreased oxygen consumption, with the effects of AgRP being more prolonged. In contrast, orexin-A increased both feeding and oxygen consumption, consistent with an observed increase in activity. The potent anorexigenic effects of CRF were accompanied by a prolonged increase in activity, whereas NMU injection resulted in significant but short-lasting inhibition of food intake, ambulatory activity and oxygen consumption. alpha-MSH injection resulted in significant increases in both ambulatory activity and oxygen consumption, and reduced food intake following administration of 3 nmol of the peptide., Conclusion: We have for the first time, simultaneously measured several metabolic parameters following hypothalamic administration of a number of neuropeptides within the same experimental system. This work has shown the interrelated effects of these neuropeotides on activity, energy expenditure and food intake, thus facilitating comparison between the different hypothalamic systems.

Peptide YY (PYY) is secreted postprandially from the endocrine L cells of the gastrointestinal tract. PYY(3-36), the major circulating form of the peptide, is thought to reduce food intake in humans and rodents via high-affinity binding to the autoinhibitory neuropeptide Y (NPY) receptor within the arcuate nucleus. We studied the effect of early light-phase injection of PYY(3-36) on food intake in mice fasted for 0, 6, 12, 18, 24, and 30 h and show that PYY(3-36) produces an acute anorexigenic effect regardless of the duration of fasting. We also show evidence of a delayed orexigenic effect in ad libitum-fed mice injected with PYY(3-36) in the early light phase. This delayed orexigenic effect also occurs in mice administered a potent analog of PYY(3-36), d-Allo Ile(3) PYY(3-36), but not following injection of other anorectic agents (glucagon-like-peptide 1, oxyntomodulin, and lithium chloride). Early light-phase injection of PYY(3-36) to ad libitum-fed mice resulted in a trend toward increased levels of hypothalamic NPY and agouti-related peptide mRNA and a decrease in proopiomelanocortin mRNA at the beginning of the dark phase. Furthermore, plasma levels of ghrelin were increased significantly, and there was a trend toward decreased plasma PYY(3-36) levels at the beginning of the dark phase. These data indicate that PYY(3-36) injection results in an acute anorexigenic effect followed by a delayed orexigenic effect.

Background: SR141716 has been shown to significantly inhibit food intake and reduce body weight by antagonizing CB(1) receptors. The gut hormones peptide YY(3-36) (PYY(3-36)) and oxyntomodulin (OXM) inhibit food intake through Y(2) and Glucagon-Like-Peptide (GLP)-1 receptors respectively., Objective: To determine the effects of co-administration of SR141716 with either PYY(3-36) or OXM in mice on food intake., Methods: Mice (n = 14 per group) were fasted for 16 h prior to study days and given two intraperitoneal injections: study 1, vehicle-saline, SR141716-saline, vehicle-PYY3-36 or SR141716-PYY3-36; study 2: vehicle-saline, SR141716-saline, vehicle-OXM or SR141716-OXM. Food was returned and measured following injections., Results: Co-administration of SR141716-PYY(3-36) or SR141716-OXM showed greater inhibition in food intake when compared with administration of SR141716, PYY(3-36) or OXM alone., Conclusion: Our data show that SR141716 in combination with PYY(3-36) or OXM reduces food intake additively in mice.

Hormonal satiety signals secreted by the gut play a pivotal role in the physiological control of appetite. However, therapeutic exploitation of the gut-brain axis requires greater insight into the interaction of gut hormones with CNS circuits of appetite control. Using the manganese ion (Mn2+) as an activity-dependent magnetic resonance imaging (MRI) contrast agent, we showed an increase in signal intensity (SI) in key appetite-regulatory regions of the hypothalamus, including the arcuate, paraventricular, and ventromedial nuclei, after peripheral injection of the orexigenic peptide ghrelin. Conversely, administration of the anorexigenic hormone peptide YY(3-36) caused a reduction in SI. In both cases, the changes in SI recorded in the hypothalamic arcuate nucleus preceded the effect of these peptides on food intake. Intravenous Mn2+ itself did not significantly alter ghrelin-mediated expression of the immediate early gene product c-Fos, nor did it cause abnormalities of behavior or metabolic parameters. We conclude that manganese-enhanced MRI constitutes a powerful tool for the future investigation of the effects of drugs, hormones, and environmental influences on neuronal activity.

Previously, we have shown that low-dose tri-iodothyronine (T3) increases food intake in rodents. This randomised, double-blind, placebo-controlled study aimed to investigate the effects of low-dose T3 on food intake in normal body weight individuals. However, despite an elevation in fT3 comparable to our earlier studies, administration of low-dose T3 in the fasted state did not stimulate food intake in man.

Background: Oxyntomodulin has recently been found to decrease body-weight in obese humans and may be a potential anti-obesity therapy., Objective: To determine whether oxyntomodulin alters energy expenditure, in addition to reducing energy intake, in 'free-living' overweight and obese volunteers., Design: Randomized double-blind controlled cross-over trial., Setting: Community and hospital-based., Participants: Fifteen healthy overweight and obese men and women (age: 23-49 years, BMI: 25.1-39.0 kg/m(2)). All volunteers completed the study protocol., Interventions: Four-day subcutaneous self-administration of pre-prandial oxyntomodulin, three times daily. Participants were advised to maintain their normal dietary and exercise regimen., Measurements: (1) Energy expenditure, measured by indirect calorimetry and combined heart rate and movement monitoring; (2) energy intake, measured during a study meal., Results: Oxyntomodulin administration reduced energy intake at the study meal by 128+/-29 kcal (P=0.0006) or 17.3+/-5.5% (P=0.0071), with no change in meal palatability. Oxyntomodulin did not alter resting energy expenditure; but increased activity-related energy expenditure by 143+/-109 kcal/day or 26.2+/-9.9% (P=0.0221); total energy expenditure by 9.4+/-4.8% (P=0.0454) and physical activity level by 9.5+/-4.6% (P=0.0495). A reduction in body weight of 0.5+/-0.2% was observed during the oxyntomodulin administration period (P=0.0232)., Conclusion: Oxyntomodulin increases energy expenditure while reducing energy intake resulting in negative energy balance. This data supports the role of oxyntomodulin as a potential anti-obesity therapy.

The effects of acute and repeated intraparaventricular (iPVN) administration of human relaxin-3 (H3) were examined on food intake, energy expenditure, and the hypothalamo-pituitary thyroid axis in male Wistar rats. An acute high dose iPVN injection of H3 significantly increased food intake 1 h post-administration [0.4+/-0.1 g (vehicle) vs 1.6+/-0.5 g (180 pmol H3), 2.4+/-0.5 g (540 pmol H3) and 2.2+/-0.5 g (1,620 pmol H3), p<0.05 for all doses vs vehicle]. Repeated iPVN H3 injection (180 pmol/twice a day for 7 days) significantly increased cumulative food intake in ad libitum fed animals compared with vehicle [211.8+/-7.1 g (vehicle) vs 261.6+/-6.7 g (ad libitum fed H3), p<0.05]. Plasma leptin was increased in the H3 ad libitum fed group. Plasma thyroid stimulating hormone was significantly decreased after acute and repeated administration of H3. These data suggest H3 may play a role in long-term control of food intake.

Intracerebroventricular (ICV) administration of the hypothalamic neuropeptide neuromedin U (NMU) or the adipostat hormone leptin increases plasma ACTH and corticosterone. The relationship between leptin and NMU in the regulation of the hypothalamo-pituitary adrenal (HPA) axis is currently unknown. In this study, leptin (1 nm) significantly increased the release of CRH from ex vivo hypothalamic explants by 207 +/- 8.4% (P < 0.05 vs. basal), an effect blocked by the administration of anti-NMU IgG. The ICV administration of leptin (10 mug, 0.625 nmol) increased plasma ACTH and corticosterone 20 min after injection [plasma ACTH (picograms per milliliter): vehicle, 63 +/- 20, leptin, 135 +/- 36, P < 0.05; plasma corticosterone (nanograms per milliliter): vehicle, 285 +/- 39, leptin, 452 +/- 44, P < 0.01]. These effects were partially attenuated by the prior administration of anti-NMU IgG. Peripheral leptin also stimulated ACTH release, an effect attenuated by prior ICV administration of anti-NMU IgG. We examined the diurnal pattern of hypothalamic NMU mRNA expression and peptide content, plasma leptin, and plasma corticosterone. The diurnal changes in hypothalamic NMU mRNA expression were positively correlated with hypothalamic NMU peptide content, plasma corticosterone, and plasma leptin. The ICV administration of anti-NMU IgG significantly attenuated the dark phase rise in corticosterone [corticosterone (nanograms per milliliter): vehicle, 493 +/- 38; NMU IgG, 342 +/- 47 (P < 0.05)]. These studies suggest that NMU may play a role in the regulation of the HPA axis and partially mediate leptin-induced HPA stimulation.

The present series of studies aimed to further our understanding of the role of melanin-concentrating hormone (MCH) neurones in the central regulation of luteinising hormone (LH) release in the female rat. LH release was stimulated when MCH was injected bilaterally into the rostral preoptic area (rPOA) or medial preoptic area (mPOA), but not when injected into the zona incerta (ZI), of oestrogen-primed ovariectomised rats. In rats that were steroid-primed to generate a surge-like release of LH, MCH administration into the ZI blocked this rise in LH release: no such effect occurred when MCH was injected into the rPOA or mPOA. In vitro, MCH stimulated gonadotrophin-releasing hormone (GnRH) release from hypothalamic explants. Double-label immunohistochemistry showed GnRH-immunoreactive neurones in the vicinity of and intermingled with immunoreactive MCH processes. MCH is the endogenous ligand of the MCH type 1 receptor (MCH1-R). Previously, we have shown a role for melanocortin-5 receptors (MC5-R) in the stimulatory action of MCH, so we next investigated the involvement of both MCH1-R and/or MC5-R in mediating the actions of MCH on GnRH and hence LH release. The stimulatory action of MCH in the rPOA was inhibited by administration of antagonists for either MCH1-R or MC5-R. However, in the mPOA, the action of MCH was blocked only by the MC5-R antagonist. LH release was stimulated by an agonist for MC5-R injected into the rPOA or mPOA; this was blocked by the MC5-R antagonist but not the MCH1-R antagonist. These results indicate that both MCH1-R and MC5-R are involved in the central control of LH release by MCH.

Objective: Abnormalities of the melanocortin system produce obesity and increased linear growth. While the obesity phenotype is well characterised, the mechanism responsible for increased linear growth is unclear. The somatotrophic axis was studied in the obese agouti (A(y)/a) mouse as a model of a perturbed melanocortin system., Design: Adult obese A(y)/a mice were compared to age- and sex-matched wild-type (WT) controls. Weight and body length (nose-anus) were recorded. Plasma growth hormone (GH), insulin-like growth factor-I (IGFI), insulin and leptin were measured using radioimmunoassay. Since ghrelin is a potent GH secretagogue, plasma ghrelin, stomach ghrelin peptide and stomach ghrelin mRNA expression were studied. Hypothalamic periventricular (PeVN) somatostatin neurones and arcuate (Arc) neuropeptide Y (NPY) neurones inhibit the growth axis, whereas Arc growth hormone-releasing hormone (GHRH) neurones are stimulatory. Therefore, specific hypothalamic expression of somatostatin, NPY and GHRH was measured using quantitative in situ hybridisation., Results: Obese A(y)/a mice were significantly heavier and longer than WT controls. Plasma IGFI concentrations were 30% greater in obese A(y)/a mice. Obese A(y) /a mice were hyperinsulinaemic and hyperleptinaemic, yet plasma ghrelin, and stomach ghrelin peptide and mRNA were significantly reduced. In obese A(y)/a mice, PeVN somatostatin and Arc NPY mRNA expression were reduced by 50% compared to WT controls, whereas Arc GHRH mRNA expression was unchanged., Conclusion: Increased body length in adult obese A(y)/a mice may result from reduced Arc NPY and PeVN somatostatin mRNA expression, which in turn, may increase plasma IGFI concentrations and upregulate the somatotrophic axis.

Background: The gastric hormone ghrelin appears a useful agent to stimulate food intake in people with anorexia of illness. The loss of ghrelin's acyl group renders it inactive, thus it has been thought that subcutaneous administration may be problematic., Objective: To investigate whether human subjects are sensitive to the effects of ghrelin administered by single subcutaneous injection., Study Design: Randomized, double-blind, placebo-controlled trial., Subjects: Sixteen healthy lean volunteers (eight men and eight women)., Protocol: Fasted subjects received subcutaneous injections of ghrelin (3.6 nmol/kg) or saline. After 30 min, a buffet breakfast was served., Results: Ghrelin injection increased energy intake by 27% (ghrelin 5076 +/- 691 kJ versus saline 4230+/-607 kJ, P = 0.04). Ghrelin appeared to enhance the perceived palatability of the food offered (palatability score: ghrelin 81.1 +/- 3.6 versus saline 70.0 +/- 4.4; P = 0.03)., Conclusions: These results suggest that subcutaneous ghrelin is effective at stimulating energy intake and improving palatability and may be of direct use in the treatment of appetite loss.

Recent studies of transgenic mice and humans have provided compelling evidence for the importance of the hypothalamic melanocortin system in the regulation of energy balance. Energy homeostasis is a balance between food intake (energy input) and energy expenditure. The melanocortin system regulates feeding via effects of the endogenous agonist, alpha-melanocyte stimulating hormone (alpha-MSH) and the endogenous antagonist agouti-related protein (AGRP) on melanocortin 3 and 4 receptors (MC3-Rs and MC4-Rs). It has been demonstrated that the melanocortin system interacts with the hypothalamo-pituitary-thyroid (HPT) axis. Thyroid hormones influence metabolism and hence energy expenditure. Therefore, an interaction between the HPT axis and the melanocortin system would allow control of both sides of the energy balance equation, by the regulation of both energy input and energy expenditure. Here we will discuss the evidence demonstrating interactions between the melanocortin system and the HPT axis.

Objective: Peptide YY3-36 (PYY(3-36)), glucagon-like peptide-1 (GLP-1), oxyntomodulin and cholecystokinin (CCK) are gastrointestinal-derived hormones that are released postprandially in proportion to the amount of calories ingested. All significantly reduce food intake following peripheral administration to rodents. We have investigated the effect of handling, exposure to a novel environment or to environmental enrichment on the anorectic effect of these gut hormones., Results: Results suggest that the transfer of a rat into a novel environment (cage change) inhibits the anorectic response to peripherally administered PYY(3-36) and oxyntomodulin (1 h food intake reduction (% saline control): PYY/home cage 82.3 +/- 5.9%, P < 0.05; PYY/clean cage 103.4 +/- 9.7%; oxyntomodulin/home cage 71.6 +/- 12.1%, P < 0.05; oxyntomodulin/clean cage 103.0 +/- 8.5%) and attenuates the anorectic response to GLP-1 and CCK (1 h food intake reduction (% saline control): GLP-1/home cage 68.8 +/- 6.4%, P < 0.01; GLP-1/clean cage 80.0 +/- 9.3%; CCK/home cage 49.8 +/- 6.2%, P < 0.001; CCK/clean cage 69.4 +/- 10.6%, P < 0.05). We have also observed that exposure to a novel environment does not alter anorectic effect of peripherally administered melanocortin 3/4 receptor agonist, melanotan II (MTII) (1 h food intake reduction (% saline control): MTII/home cage 32.0 +/- 6.3%, P < 0.001; MTII/clean cage 24.8 +/- 4.2%, P < 0.001). The attenuation in food intake observed following exposure to a novel environment can be attributed, in part, to a significant reduction in the food intake of the saline treated animals. In a further study, the anorectic effect of peripherally administered PYY(3-36) is attenuated in unhandled rats (88 +/- 4.2% saline control, P = ns) or rats exposed to environmental enrichment (103.3 +/- 9.7% saline control, P = ns), but not in animals that were handled extensively prior to the study (80.1 +/- 7.3% saline control, P < 0.05)., Conclusion: These studies highlight the importance of handling, acclimatisation and habituation of rodents to experimental conditions prior to investigating the ability of gut hormones to alter food intake.

Peptide YY (PYY) and glucagon like peptide (GLP)-1 are cosecreted from intestinal L cells, and plasma levels of both hormones rise after a meal. Peripheral administration of PYY(3-36) and GLP-1(7-36) inhibit food intake when administered alone. However, their combined effects on appetite are unknown. We studied the effects of peripheral coadministration of PYY(3-36) with GLP-1(7-36) in rodents and man. Whereas high-dose PYY(3-36) (100 nmol/kg) and high-dose GLP-1(7-36) (100 nmol/kg) inhibited feeding individually, their combination led to significantly greater feeding inhibition. Additive inhibition of feeding was also observed in the genetic obese models, ob/ob and db/db mice. At low doses of PYY(3-36) (1 nmol/kg) and GLP-1(7-36) (10 nmol/kg), which alone had no effect on food intake, coadministration led to significant reduction in food intake. To investigate potential mechanisms, c-fos immunoreactivity was quantified in the hypothalamus and brain stem. In the hypothalamic arcuate nucleus, no changes were observed after low-dose PYY(3-36) or GLP-1(7-36) individually, but there were significantly more fos-positive neurons after coadministration. In contrast, there was no evidence of additive fos-stimulation in the brain stem. Finally, we coadministered PYY(3-36) and GLP-1(7-36) in man. Ten lean fasted volunteers received 120-min infusions of saline, GLP-1(7-36) (0.4 pmol/kg.min), PYY(3-36) (0.4 pmol/kg.min), and PYY(3-36) (0.4 pmol/kg.min) + GLP-1(7-36) (0.4 pmol/kg.min) on four separate days. Energy intake from a buffet meal after combined PYY(3-36) + GLP-1(7-36) treatment was reduced by 27% and was significantly lower than that after either treatment alone. Thus, PYY(3-36) and GLP-1(7-36), cosecreted after a meal, may inhibit food intake additively.

Intracerebroventricular (ICV) administration of Neuromedin U (NMU), a hypothalamic neuropeptide, or leptin, an adipostat hormone released from adipose tissue, reduces food intake and increases energy expenditure. Leptin stimulates the release of NMU in vitro, and NMU expression is reduced in models of low or absent leptin. We investigated the role of NMU in mediating leptin-induced satiety. ICV administration of anti-NMU immunoglobulin G (IgG) (5 nmol) to satiated rats significantly increased food intake 4 h after injection, an effect seen for

Context: Patients with gastric or esophageal surgery and transection of the vagus nerve may suffer from appetite and weight loss but without dysphagia or mechanical obstruction to eating. The gastric hormone ghrelin stimulates food intake and GH release in rodents and man. However, rodents with vagotomy are not sensitive to the feeding effects of ghrelin., Objective: The objective of the study was to determine whether humans with vagotomy are sensitive to ghrelin., Study Design: The design was a double-blind, randomized, placebo-controlled trial., Setting: This was a hospital-based study., Patients: Six men and one woman who all had a previous complete truncal vagotomy with lower esophageal or gastric surgery entered and completed the study., Intervention: Each patient received 120-min infusions of saline, 1 pmol/kg.min ghrelin, and 5 pmol/kg.min ghrelin on 3 separate days. After 90 min, a buffet meal was served., Main Outcome Measure: Energy intake at the buffet meal was measured., Results: Ghrelin-stimulated GH release in a dose-dependent manner was measured, confirming bioactivity. However, no change in energy intake was observed with either dose of ghrelin [energy intake (kilojoules): saline 2805 +/- 812; ghrelin 1 pmol/kg.min, 2486 +/- 767; ghrelin 5 pmol/kg.min, 2382 +/- 543; P = not significant]., Conclusions: Ghrelin is unlikely to be an effective appetite-stimulatory treatment for patients with vagotomy and esophageal or gastric surgery. Our results suggest that an intact vagus nerve may be required for exogenous ghrelin to increase appetite and food intake in man.

Anorexia and malnutrition confer significant morbidity and mortality to patients with end-stage kidney disease but are resistant to therapy. The aim of this study was to determine whether subcutaneous administration of ghrelin, an appetite-stimulating gut hormone, could enhance food intake in patients who are receiving maintenance peritoneal dialysis and have evidence of malnutrition. The principal outcome measure was energy intake during a measured study meal. Secondary outcome measures were BP and heart rate and 3-d food intake after intervention. Nine peritoneal dialysis patients with mild to moderate malnutrition (mean serum albumin 28.6 +/- 5.0 g/L, total cholesterol 4.4 +/- 0.6 mmol/L, subjective global assessment score of 5.7 +/- 1.7) were given subcutaneous ghrelin (3.6 nmol/kg) and saline placebo in a randomized, double-blind, crossover protocol. Administration of subcutaneous ghrelin significantly increased the group mean absolute energy intake, compared with placebo, during the study meal (690 +/- 190 versus 440 +/- 250 kcal; P = 0.0062). When expressed as proportional energy increase for each individual, ghrelin administration resulted in immediate doubling of energy intake (204 +/- 120 versus 100%; P = 0.0319). Administration of ghrelin maintained a nonsignificant increase in energy intake over 24 h after intervention (2009 +/- 669 versus 1579 +/- 330 kcal) and was not followed by subsequent underswing (1790 +/- 370 versus 1670 +/- 530 and 1880 +/- 390 versus 1830 +/- 530 kcal on days 2 and 3, respectively). Ghrelin administration resulted in a significant fall in mean arterial BP (P = 0.0030 by ANOVA). There were no significant adverse events during the study. Subcutaneous ghrelin administration enhances short-term food intake in dialysis patients with mild to moderate malnutrition.

The vagus nerve forms a neuro-anatomical link between the gastrointestinal tract and the brain. A number of gastrointestinal hormones, including cholecystokinin and ghrelin, require an intact vagal-brainstem-hypothalamic pathway to affect CNS feeding circuits. We have shown that the effects of peripheral administration of both peptide YY(3-36) (PYY(3-36)) and glucagon-like peptide-1 (GLP-1) on food intake and activation of hypothalamic arcuate feeding neurones are abolished following either bilateral sub-diaphragmatic total truncal vagotomy or brainstem-hypothalamic pathway transectioning in rodents. These findings suggest that the vagal-brainstem-hypothalamic pathway may also play a role in the effects of circulating PYY(3-36) and GLP-1 on food intake.

The gastrointestinal-derived hormone peptide YY (PYY) is released from intestinal L-cells post-prandially in proportion to calorie intake, and modulates food intake. Peripheral administration of PYY((3-36)) reduces food intake and body weight in rodents and suppresses appetite and food intake in humans. PYY((3-36)) is hypothesised to inhibit food intake via activation of the auto-inhibitory pre-synaptic neuropeptide Y (NPY) Y2 receptor (Y2R) present on arcuate (ARC) NPY neurons. We aimed to investigate the feeding effect of PYY((3-36)) following blockade of ARC Y2R, using the specific receptor antagonist BIIE0246, in the rat. We found that pre-treatment with BIIE0246 (1 nmol) into the ARC attenuated the reduction in feeding observed following intraperitoneal injection of PYY((3-36)) (7.5 nmol/kg) (0-1 h food intake: BIIE0246/PYY((3-36)): 3.8 +/- 0.4 g; vs. Vehicle/PYY((3-36)): 2.7 +/- 0.2 g; P < 0.05). We found plasma PYY levels to be maximal at 120 min post-initiation of feeding. On investigation of the endogenous role of the Y2R, we found that ARC administration of BIIE0246 alone significantly increased feeding in satiated rats compared to vehicle-injected controls (0-1 h food intake: BIIE0246: 4.1 +/- 0.7 g; vs. vehicle: 1.7 +/- 0.7 g; P < 0.05), suggesting that Y2R antagonism disinhibits the NPY neuron thus stimulating feeding in otherwise satiated rats. These studies suggest that the Y2R plays an important role in post-prandial satiety and provide further insight into the mechanisms of action of PYY((3-36)).

Many peptides are synthesised and released from the gastrointestinal tract. Although their roles in the regulation of gastrointestinal function have been known for some time, it has become increasingly evident that they also influence eating behaviour. Peptide YY (PYY) is released postprandially from gastrointestinal L-cells with glucagon-like peptide 1 (GLP-1) and oxyntomodulin. Following peripheral administration of PYY3-36, the circulating form of PYY, to mouse, rat or human there is marked inhibition of food intake. Obese subjects have lower basal fasting PYY levels and have a smaller postprandial rise. However, obesity does not appear to be associated with resistance to PYY (as it is with leptin) and exogenous infusion of PYY3-36 results in a reduction in food intake by 30% in an obese group and 31% in a lean group at a buffet meal. Overall PYY significantly reduced 24-h caloric intake in both obese (16.5%) and lean groups (23.5%). Obesity is the current major cause of premature death in the UK, killing almost 1000 people a week. Worldwide its prevalence is accelerating. The administration of the naturally occurring gut hormone may offer a long-term therapeutic approach to weight control. Here, the therapeutic potential of PYY is considered.

Recent studies have demonstrated that AMP-activated protein kinase (AMPK) in the hypothalamus is involved in the regulation of food intake. Because exercise is known to influence appetite and cause substrate depletion, it may also influence AMPK in the hypothalamus. Male rats that either rested or ran for 30 or 60 min on a treadmill (22 m/min, 10% slope) were sacrificed immediately after exercise or after 60 min recovery either in the fasted state or after oral gavage with glucose (3g/kg body weight). Exercise decreased muscle and liver glycogen substantially. Hypothalamic total or alpha2-associated AMPK activity and phosphorylation state of the AMPK substrate acetyl-CoA carboxylase were not changed significantly immediately following treadmill running or during fed or fasted recovery. Plasma ghrelin increased (P<0.05) by 40% during exercise whereas the concentration of PYY was unchanged. In recovery, glucose feeding increased plasma glucose and insulin concentrations whereas ghrelin and PYY decreased to (ghrelin) or below (PPY) resting levels. It is concluded that 1h of strenuous exercise in rats does not elicit significant changes in hypothalamic AMPK activity despite an increase in plasma ghrelin. Thus, changes in energy metabolism during or after exercise are likely not coordinated by changes in hypothalamic AMPK activity.

Obesity is currently the major cause of premature death in the UK, killing almost 1000 individuals per week, and worldwide, its prevalence is accelerating. Many peptides are synthesized and released from the gastrointestinal tract and, while their roles in the regulation of gastrointestinal function have been known for some time, it is now evident that they also physiologically influence eating behavior. Therefore, manipulation of gastrointestinal hormones provides the prospect of an effective and well-tolerated treatment for obesity. Whereas drugs targeting appetite-signaling neuropeptides in the brain may also affect other aspects of the central nervous system, agents based on gut hormones themselves have the advantage of targeting specific appetite circuits within the brain without producing any unacceptable side effects.

The melanocortin system is an important regulator of body weight and the hypothalamo-pituitary-thyroid (HPT) axis. The pro-opiomelanocortin (POMC)-null mouse, deficient in all POMC-derived peptides, including alpha-melanocyte stimulating hormone (alpha-MSH), has an obese phenotype. We studied the HPT axis of POMC-null mice, which has not been previously investigated. Because alpha-MSH has a stimulatory effect on the HPT axis, we hypothesised that these mice would have a down-regulated thyroid axis, consistent with a recent study of POMC-null humans. The activity of the HPT axis was studied by collecting blood, pituitaries and hypothalami from ad libitum fed, adult POMC-null, heterozygous and wild-type mice. POMC-null mice had significantly elevated plasma total T(4) (TT(4)) and free T(3) (fT(3)) with reduced plasma thyroid stimulating hormone (TSH), pituitary TSH content and hypothalamic thyrotrophin stimulating hormone (TRH) content compared to wild-type mice. No significant differences between heterozygous and wild-type mice were observed. POMC-null mice have an abnormal HPT axis, which may contribute to their hyperphagia and obesity. These abnormalities are in contrast to those observed in POMC-null humans. These findings support a role for the melanocortin system in the regulation of the HPT axis.

Increased food intake is characteristic of hyperthyroidism, although this is presumed to compensate for a state of negative energy balance. However, here we show that the thyroid hormone T(3) directly stimulates feeding at the level of the hypothalamus. Peripheral administration of T(3) doubled food intake in ad libitum-fed rats over 2 h and induced expression of the immediate early gene, early growth response-1, in the hypothalamic ventromedial nucleus (VMN), whereas maintaining plasma-free T(3) levels within the normal range. T(3)-induced feeding occurred without altering energy expenditure or locomotion. Injection of T(3) directly into the VMN produced a 4-fold increase in food intake in the first hour. The majority of T(3) in the brain is reported to be produced by tissue-specific conversion of T(4) to T(3) by the enzyme type 2 iodothyronine deiodinase (D2). Hypothalamic D2 mRNA expression showed a diurnal variation, with a peak in the nocturnal feeding phase. Hypothalamic D2 mRNA levels also increased after a 12- and 24-h fast, suggesting that local production of T(3) may play a role in this T(3) feeding circuit. Thus, we propose a novel hypothalamic feeding circuit in which T(3), from the peripheral circulation or produced by local conversion, stimulates food intake via the VMN.

Hypothalamic neuromedin U (NMU) appears to have a role in the regulation of appetite and the hypothalamo-pituitary-adrenal (HPA) axis. Acute administration of NMU into the paraventricular nuclei (iPVN) increases plasma adrenocorticotrophic hormone and corticosterone, and inhibits food intake in fasted rats. No studies have as yet investigated the chronic effects of centrally administered NMU. We investigated the effect of twice-daily iPVN injections of 0.3 nmol NMU for 7 days on food intake, body weight, the HPA axis, and behavior in freely fed rats. Chronic iPVN NMU was not associated with a decrease in food intake or body weight. Chronic iPVN NMU produced a typical behavioral response on day 1 and day 4 of the study, and resulted in the elevation of plasma corticosterone present 18 h after the final injection. These results suggest NMU may have a role in the regulation of the HPA axis and behavior., (Copyright 2004 Elsevier Inc.)

Many peptides are synthesised and released from the gastrointestinal tract. Whilst their roles in regulation of gastrointestinal function have been known for some time, it is now evident that they also influence eating behaviour and thus potential anti obesity targets. Peptide YY (PYY) is released post prandially from the gastrointestinal L-cells with glucagon-like peptide 1 (GLP-1) and oxyntomodulin. Following peripheral administration of PYY 3-36, the circulating form of PYY, to mouse, rat or human there is marked inhibition of food intake. PYY 3-36 is thought to mediate its actions through the NPY Y2 GPCR. Obese subjects have lower basal fasting PYY levels and have a smaller post prandial rise. However, obesity does not appear to be associated with resistance to PYY (as it is with leptin) and exogenous infusion of PYY 3-36 results in a reduction in food intake by 30% in an obese group and 31% in a lean group. GLP-1 or oxyntomodulin, products of the prepreglucagon gene, decrease food intake when administered either peripherally or directly into the CNS. In addition, both have been shown to decrease food intake in humans. These effects are thought to be mediated by the GLP-1 receptor. Ghrelin, a huger hormone produced by the stomach, increases in the circulation following a period of fasting. Administration of ghrelin either peripherally or directly into the CNS increases food intake and chronic administration leads to obesity. Further infusion into normal healthy volunteers increases both food intake and appetite. Ghrelin is thought to act through the growth hormone secretagogue receptor (GHS-R). Obesity is the current major cause of premature death in the UK, killing almost 1000 people a week. Worldwide its prevalence is accelerating. The administration of the naturally occurring gut hormone may offer a long-term therapeutic approach to weight control. Here we consider the therapeutic potential of some gut hormones, and the GPCR's through which they act, in the treatment of obesity.

Cocaine- and amphetamine-regulated transcript (CART) was originally isolated from rat brain, but CART is also synthesized and stored in the anterior pituitary. The localization of pituitary CART and factors regulating its synthesis are largely unknown. The regulation of pituitary CART synthesis and release in response to CRH and glucocorticoids was examined in vitro and in vivo. CART immunoreactivity (CART-IR) was released from anterior pituitary segments. This release was increased 15-fold in response to corticotropin-releasing hormone (CRH). Intraperitoneal administration of CRH to rats significantly increased plasma CART-IR. Furthermore, CART-IR content and plasma CART-IR were significantly increased in adrenalectomized rats, and anterior pituitary CART mRNA expression, CART-IR content, and plasma CART-IR were significantly decreased in corticosterone-treated rats. Plasma CART-IR showed a pattern of diurnal variation similar to that of ACTH and corticosterone, and plasma CART-IR was positively correlated with corticosterone. CART-IR was detectable in the medium of the corticotroph cell line AtT-20. Dual in situ hybridization for prepro-CART (ppCART) mRNA expression and immunocytochemistry for ACTH showed localization of ppCART mRNA to a subpopulation of ACTH-immunoreactive cells. These findings demonstrate that pituitary CART expression and release are regulated by CRH and the glucocorticoid environment and that pituitary CART is partly localized to corticotrophs.

Obesity is the main cause of premature death in the UK. Worldwide its prevalence is accelerating. It has been hypothesized that a gut nutriment sensor signals to appetite centres in the brain to reduce food intake after meals. Gut hormones have been identified as an important mechanism for this. Ghrelin stimulates, and glucagon like peptide-1, oxyntomodulin, peptide YY (PYY), cholecystokinin and pancreatic polypeptide inhibit, appetite. At physiological postprandial concentrations they can alter food intake markedly in humans and rodents. In addition, in obese humans fasting levels of PYY are suppressed and postprandial release is reduced. Administration of gut hormones might provide a novel and physiological approach in anti-obesity therapy. Here, we summarize some of the recent advances in this field.

Objective: The role of the melanocortin system in the feeding effects of peripheral peptide YY(3-36) (PYY(3-36)) and ghrelin was investigated using the agouti (A(y)/a) mouse as a model of abnormal melanocortin signalling. Furthermore, we examined whether the ectopic expression of agouti protein in A(y)/a mice results in complete MC4-R inhibition, by studying the effects of peripheral alpha-melanocyte-stimulating hormone (alpha-MSH) and leptin on food intake., Design: Adult A(y)/a mice were studied in the pre-obese state (7-8 weeks) and obese state (14-15 weeks). Animals received PYY(3-36) (0.02 micromol/kg), NDP-alpha-MSH (0.2 micromol/kg), leptin (2 micromol/kg) (all 24 h fasted state) and ghrelin (0.2 micromol/kg) (fed state) by intraperitoneal (i.p.) injection. Age-matched A(y)/a controls received i.p. saline. A separate cohort of wild-type (WT), age-matched controls received the same peptide dose or saline. Food intake was measured at 1, 2, 4, 8 and 24 h post-injection and compared in all four groups. Plasma leptin-, ghrelin- and PYY-like immunoreactivity (IR) were measured using radioimmunoassay (RIA)., Results: At 2 h post-injection, PYY(3-36) reduced food intake in pre-obese and obese A(y)/a mice, whereas ghrelin had no effect. Plasma ghrelin levels were significantly reduced in pre-obese and obese A(y)/a mice compared to WT controls. Peripheral administration of NDP-alpha-MSH and leptin acutely suppressed feeding (0-2 h) in pre-obese and obese A(y)/a mice., Conclusions: Responsiveness of pre-obese and obese A(y)/a mice to PYY(3-36) suggests that the melanocortin system may not be essential for the anorectic effects of this peptide. Melanocortinergic antagonism by agouti protein in A(y)/a mice may be sufficient to block the effects of endogenous, but not exogenous PYY(3-36), alpha-MSH and leptin. The mechanism underlying ghrelin resistance in A(y)/a mice may result from antagonism of hypothalamic melanocortin receptors-4 by agouti protein, supporting a role for the melanocortin system in mediating ghrelin's actions.

Oxyntomodulin (OXM) is a circulating gut hormone released post prandially from cells of the gastrointestinal mucosa. Given intracerebroventricularly to rats, it inhibits food intake and promotes weight loss. Here we report that peripheral (ip) administration of OXM dose-dependently inhibited both fast-induced and dark-phase food intake without delaying gastric emptying. Peripheral OXM administration also inhibited fasting plasma ghrelin. In addition, there was a significant increase in c-fos immunoreactivity, a marker of neuronal activation, in the arcuate nucleus (ARC). OXM injected directly into the ARC caused a potent and sustained reduction in refeeding after a fast. The anorectic actions of ip OXM were blocked by prior intra-ARC administration of the glucagon-like peptide-1 (GLP-1) receptor antagonist, exendin(9-39), suggesting that the ARC, lacking a complete blood-brain barrier, could be a potential site of action for circulating OXM. The actions of ip GLP-1, however, were not blocked by prior intra-ARC administration of exendin(9-39), indicating the potential existence of different OXM and GLP-1 pathways. Seven-day ip administration of OXM caused a reduction in the rate of body weight gain and adiposity. Circulating OXM may have a role in the regulation of food intake and body weight.

The gastrointestinal tract and the pancreas release hormones regulating satiety and body weight. Ghrelin stimulates appetite, and glucagon-like peptide-1, oxyntomodulin, peptide YY, cholecystokinin, and pancreatic polypeptide inhibit appetite. These gut hormones act to markedly alter food intake in humans and rodents. Obesity is the current major cause of premature death in the United Kingdom, killing almost 1000 people per week. Worldwide, its prevalence is accelerating. There is currently no effective answer to the pandemic of obesity, but replacement of the low levels of peptide YY observed in the obese may represent an effective antiobesity therapy.

There is a pressing need for more effective appetite-stimulatory therapies for many patient groups including those with cancer. We have previously demonstrated that the gastric hormone ghrelin potently enhances appetite in healthy volunteers. Here, we performed an acute, randomized, placebo-controlled, cross-over clinical trial to determine whether ghrelin stimulates appetite in cancer patients with anorexia. Seven cancer patients who reported loss of appetite were recruited from oncology clinics at Charing Cross Hospital. The main outcome measures were energy intake from a buffet meal during ghrelin or saline infusion and meal appreciation as assessed by visual analog scale. A marked increase in energy intake (31 +/- 7%; P = 0.005) was observed with ghrelin infusion compared with saline control, and every patient ate more. The meal appreciation score was greater by 28 +/- 8% (P = 0.02) with ghrelin treatment. No side effects were observed. The stimulatory effects of ghrelin on food intake and meal appreciation seen in this preliminary study suggest that ghrelin could be an effective treatment for cancer anorexia and possibly for appetite loss in other patient groups.