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Abstract: Acylated ghrelin and peptide YY (PYY3–36) are involved in appetite-regulation and energy homeostasis. These gastrointestinal hormones provide peripheral signals to the central nervous system to regulate appetite and short term food intake, and interact with leptin and insulin to regulate energy balance. Dietary restraint is an eating behavior phenotype that manifests as a conscious cognitive control of food intake in order to achieve or sustain a desired body weight. The purpose of the current study was to determine if college-aged women (18 to 25years) with different eating behavior phenotypes, i.e., high vs normal dietary restraint, differ with respect to circulating concentrations of gastrointestinal hormones during and following a test meal. We hypothesized that women with high dietary cognitive restraint [High CR (score≥13, n=13)] would have elevated active ghrelin and PYY3–36 concentrations after a test meal compared to women with normal dietary cognitive restraint [Normal CR (score<13, n=30)]. Gastrointestinal hormones were assessed before (−15 and 0min) and after (10, 15, 20, 30, 60, 90, 120 and 180min) the consumption of a mixed composition meal (5.0kcal per kg/body weight). In contrast to our hypothesis, mean PYY3–36 concentrations (p=0.042), peak PYY3–36 concentrations (p=0.047), and PYY3–36 area under the curve (p=0.035) were lower in the High CR group compared to the Normal CR group after controlling for body mass index. No group differences were observed with respect to acylated ghrelin before or after the meal. In conclusion, PYY3–36 concentrations were suppressed in the women with High CR compared to the women with Normal CR. While the current study is cross-sectional and cause/effect of high dietary restraint and suppressed PYY3–36 concentrations cannot be determined, we speculate that these women with high cognitive restraint may be prone to weight gain or weight re-gain related to the suppressed circulating PYY after a meal. Further investigations need to explore the relationship between dietary cognitive restraint, circulating PYY, and weight gain. [Copyright &y& Elsevier]

Abstract: Background: In women with anorexia nervosa, elevated fasting peptide YY (PYY) is associated with decreased bone mineral density (BMD). Prior research from our lab has demonstrated that fasting total PYY concentrations are elevated in exercising women with amenorrhea compared to ovulatory exercising women. Purpose: The purpose of this study was to assess the association between fasting total PYY, average monthly estrogen exposure and BMD in non-obese premenopausal exercising women. Methods: Daily urine samples were collected and assessed for metabolites of estrone 1-glucuronide (E1G) and pregnandiol glucuronide (PdG) for at least one menstrual cycle if ovulatory or a 28-day monitoring period if amenorrheic. Fasting serum samples were pooled over the measurement period and analyzed for total PYY and leptin. BMD and body composition were assessed by dual-energy X-ray absorptiometry. Multiple regression analyses were performed to determine whether measures of body composition, estrogen status, exercise minutes, leptin and PYY explained a significant amount of the variance in BMD at multiple sites. Results: Premenopausal exercising women aged 23.8±0.9years with a mean BMI of 21.2±0.4kg/m2 exercised 346±48min/week and had a peak oxygen uptake of 49.1±1.8mL/kg/min. Thirty-nine percent (17/44) of the women had amenorrhea. Fasting total PYY concentrations were negatively associated with total body BMD (p=0.033) and total hip BMD (p=0.043). Mean E1G concentrations were positively associated with total body BMD (p=0.033) and lumbar spine (L2–L4) BMD (p=0.047). The proportion of variance in lumbar spine (L2–L4) BMD explained by body weight and E1G cycle mean was 16.4% (R2 =0.204, p=0.012). The proportion of variance in hip BMD explained by PYY cycle mean was 8.6% (R2 =0.109, p=0.033). The proportion of variance in total body BMD explained by body weight and E1G cycle mean was 21.9% (R2 =0.257, p=0.003). Conclusion: PYY, mean E1G and body weight are associated with BMD in premenopausal exercising women. Thus, elevated PYY and suppressed estrogen concentrations are associated with, and could be directly contributing to, low BMD in exercising women with amenorrhea, despite regular physical activity. [Copyright &y& Elsevier]

BACKGROUND Low concentrations of leptin secondary to low body fat or other modulators are thought to be a key signal whereby an energy deficit suppresses the reproductive axis in exercising women resulting in functional hypothalamic amenorrhea (FHA). The purpose of this study was to first examine leptin concentrations in exercising women with and without FHA to address whether there is a threshold concentration of leptin below which reproductive function is suppressed. Secondly, we examined the role of adiposity and other possible modulators of leptin to ascertain whether leptin regulation differs depending on reproductive status. METHODS This study assessed 50 exercising, premenopausal women (aged 18–30 years) over the course of one menstrual cycle (eumenorrheic women) or one 28-day monitoring period (amenorrheic women). Quantification of daily urinary ovarian steroids and menstrual history were used to determine menstrual status. Body composition was assessed using dual energy X-ray absorptiometry, and leptin was determined by enzyme-linked immunoassay. Key modulators of leptin such as serum insulin concentration, carbohydrate intake, glucose availability, indirect indices of sympathetic nervous activity and other factors were assessed using linear regression. RESULTS Percentage body fat (%BF) (21.0 ± 1.0 versus 26.8 ± 0.7%; P< 0.001) and leptin concentration (4.8 ± 0.8 versus 9.6 ± 0.9 ng/ml; P< 0.001) were lower in the exercising women with amenorrhea (ExAmen; n = 24) compared with the exercising ovulatory women (ExOvul; n= 26). However, the ranges in leptin were similar for each group (ExAmen: 0.30–16.98 ng/ml; ExOvul: 2.57–18.28 ng/ml), and after adjusting for adiposity the difference in leptin concentration was no longer significant. Significant predictors of log leptin in ExAmen included %BF (β = 0.826, P< 0.001), log insulin (β = 0.308, P= 0.012) and log glycerol (β = 0.258, P= 0.030), but in ExOvul only %BF predicted leptin. CONCLUSIONS These data suggest that leptin concentrations per se are not associated with FHA in exercising women, but the modulation of leptin concentrations may differ depending on reproductive status. [ABSTRACT FROM AUTHOR]

Abstract: This study examined whether regular exercise training, at a level that would be recommended for middle-aged people interested in improving fitness could lead to improved cognitive performance and increased blood flow to the brain in another primate species. Adult female cynomolgus monkeys were trained to run on treadmills for 1 h a day, 5 days a week, for a 5 month period (n=16; 1.9±0.4 miles/day). A sedentary control group sat daily on immobile treadmills (n=8). Half of the runners had an additional sedentary period for 3 months at the end of the exercise period (n=8). In all groups, half of the monkeys were middle-aged (10–12 years old) and half were more mature (15–17 years old). Starting the fifth week of exercise training, monkeys underwent cognitive testing using the Wisconsin General Testing Apparatus (WGTA). Regardless of age, the exercising group learned to use the WGTA significantly faster (4.6±3.4 days) compared to controls (8.3±4.8 days; P=0.05). At the end of 5 months of running monkeys showed increased fitness, and the vascular volume fraction in the motor cortex in mature adult running monkeys was increased significantly compared to controls (P=0.029). However, increased vascular volume did not remain apparent after a 3-month sedentary period. These findings indicate that the level of exercise associated with improved fitness in middle-aged humans is sufficient to increase both the rate of learning and blood flow to the cerebral cortex, at least during the period of regular exercise. [Copyright &y& Elsevier]