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Gastric emptying is a major determinant of postprandial blood glucose, accounting for ~35% of variance in peak glucose in both healthy individuals and those with type 2 diabetes. Gastric emptying is frequently disordered in individuals with diabetes (both abnormally delayed and accelerated). Delayed gastric emptying, i.e. diabetic gastroparesis, may be linked to upper gastrointestinal symptoms for which current treatment remains suboptimal; pharmacological acceleration of delayed emptying is only weakly associated with symptom improvement. Accordingly, the relationship between symptoms and delayed gastric emptying is not simply ‘cause and effect’. In insulin-treated patients, disordered gastric emptying, even when not associated with gastrointestinal symptoms, can cause a mismatch between the onset of insulin action and the availability of absorbed carbohydrate, leading to suboptimal glycaemic control. In patients with type 2 diabetes, interventions that slow gastric emptying, e.g. glucagon-like peptide-1 receptor agonists, reduce postprandial blood glucose. This review focuses on recent insights into the impact of gastric emptying on postprandial blood glucose, effects of diabetes therapy on gastric emptying and the management of disordered gastric emptying in diabetes. In view of the broad relevance of gastric emptying to diabetes management, it is important that future clinical trials evaluating novel therapies that may affect gastric emptying should quantify the latter with an appropriate technique, such as scintigraphy or a stable isotope breath test. Graphical abstract

usc Aim: To determine the serum bile acid (BA) response to 75-g oral glucose in individuals without diabetes, and whether this is attenuated in patients with ‘early’ type 2 diabetes (T2D) and related to the glycaemic response at 2 hours in either group. Methods: Forty newly diagnosed, treatment-naïve Han Chinese T2D subjects and 40 age-, gender-, and body mass index-matched controls without T2D ingested a 75-g glucose drink after an overnight fast. Plasma glucose and serum concentrations of total and individual BAs, fibroblast growth factor-19 (FGF-19), total glucagon-like peptide-1 (GLP-1), and insulin, were measured before and 2 hours after oral glucose. Results: Fasting total BA levels were higher in T2D than control subjects (P

Context Premenopausal women are at a lower risk of type 2 diabetes (T2D) compared to men, but the underlying mechanism(s) remain elusive. The secretion of the incretin hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), from the small intestine is a major determinant of glucose homeostasis and may be influenced by sex. Objectives This study compared blood glucose and plasma insulin and incretin responses to intraduodenal glucose infusions in healthy young males and females. Design In Study 1, 9 women and 20 men received an intraduodenal glucose infusion at 2 kcal/min for 60 minutes. In Study 2, 10 women and 26 men received an intraduodenal glucose at 3 kcal/min for 60 minutes. Venous blood was sampled every 15 minutes for measurements of blood glucose and plasma insulin, GLP-1 and GIP. Results In response to intraduodenal glucose at 2 kcal/min, the incremental area under the curve between t = 0-60 minutes (iAUC0-60min) for blood glucose and plasma GIP did not differ between the 2 groups. However, iAUC0-60min for plasma GLP-1 (P = 0.016) and insulin (P = 0.011) were ∼2-fold higher in women than men. In response to intraduodenal glucose at 3 kcal/min, iAUC0-60min for blood glucose, plasma GIP, and insulin did not differ between women and men, but GLP-1 iAUC0-60min was 2.5-fold higher in women (P = 0.012). Conclusion Healthy young women exhibit comparable GIP but a markedly greater GLP-1 response to intraduodenal glucose than men. This disparity warrants further investigations to delineate the underlying mechanisms and may be of relevance to the reduced risk of diabetes in premenopausal women when compared to men.

Aim: To evaluate the effect of gastric distension, induced using a gastric ‘barostat’, on the secretion of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) in the presence and absence of small intestinal nutrients in healthy individuals. Materials and Methods: Eight healthy participants (two females, six males, mean age 69.3 ± 1.2 years, body mass index 23.5 ± 0.8 kg/m2) were each studied on four occasions when they received an intraduodenal infusion of either (i) 0.9% saline or (ii) glucose delivered at a rate of 3 kcal/min both with, and without, an intragastric balloon with the pressure set to 8 mmHg above the intragastric minimum distending pressure. Results: Following intraduodenal saline or glucose infusion, there was no difference in plasma GLP-1 with or without gastric distension (P = 1.00 for both saline and glucose infusions). There was also no difference in plasma GIP with or without gastric distension (P = 1.00 for saline infusion and P = .99 for glucose infusion). Conclusions: Gastric distension, either alone or during small intestinal glucose exposure, does not stimulate incretin hormone secretion significantly in healthy humans. Refereed/Peer-reviewed

Aim: To investigate whether co-ingestion of dietary protein with, or before, carbohydrate may be a useful strategy to reduce postprandial hyperglycaemia in older men with type 2 diabetes (T2D). Materials and Methods: Blood glucose, plasma insulin and glucagon concentrations were measured for 180 minutes following ingestion of a drink containing 30 g of glucose (G; 120 kcal), 30 g of whey protein (120 kcal), 30 g of glucose plus 30 g of whey protein (GP; 240 kcal), or control (~2 kcal) in older men with T2D (n = 10, 77 ± 1 years; 31 ± 1.7 kg/m2) and without T2D (n = 10, 78 ± 2 years; 27 ± 1.4 kg/m2). Mixed model analysis was used. Results: GP versus G markedly reduced the increase in blood glucose concentrations (P

Immunoglobulin G (IgG) autoantibodies reactive to fetal brain proteins in mothers of children with ASD have been described by several groups. To understand their pathologic significance, we developed a mouse model of maternal autoantibody related ASD (MAR-ASD) utilizing the peptide epitopes from human autoantibody reactivity patterns. Male and female offspring prenatally exposed to the salient maternal autoantibodies displayed robust deficits in social interactions and increased repetitive self-grooming behaviors as juveniles and adults. In the present study, neuroanatomical differences in adult MAR-ASD and control offspring were assessed via high-resolution ex vivo magnetic resonance imaging (MRI) at 6 months of age. Of interest, MAR-ASD mice displayed significantly larger total brain volume and of the 159 regions examined, 31 were found to differ significantly in absolute volume (mm3) at an FDR of

Background: Gastrointestinal symptoms have been reported to occur frequently in diabetes, but their prevalence in Chinese community-dwelling individuals with diabetes is unknown. The present study aimed to address this issue and explore the risk factors for gastrointestinal symptoms. Methods: A total of 1304 community-dwelling participants (214 with diabetes, 360 with prediabetes and 730 with normoglycemia) were surveyed for gastrointestinal symptoms using the Diabetes Bowel Symptom Questionnaire. Logistic regression analyses were applied to identify risk factors for gastrointestinal symptoms. Results: Of the overall study population, 18.6% reported at least one gastrointestinal symptom, without a significant difference between subjects with normoglycemia (17.7%), prediabetes (19.7%) and diabetes (20.1%). In all three groups, lower gastrointestinal symptoms, particularly diarrhea and constipation, were the most frequent. There was an interaction between age (≥65 years) and diabetes on the prevalence of at least one gastrointestinal symptom (p = 0.01) and of constipation (p = 0.004), with these being most frequent in subjects with diabetes aged ≥ 65 years. After multivariable adjustment, female gender and older age were associated with increased odds of at least one gastrointestinal symptom, specifically lower gastrointestinal symptoms. Older age was also associated with an increase in upper gastrointestinal symptoms. Conclusions: Gastrointestinal symptoms are common in Chinese community-dwelling adults with and without diabetes. Females, and the elderly with diabetes, are at an increased risk of symptoms. Refereed/Peer-reviewed

BACKGROUND Postprandial falls in blood pressure (BP) are more common in older compared to younger individuals. The effects of protein compared to carbohydrates and fat on postprandial BP, and the relation to gastric emptying rates, are poorly studied. OBJECTIVES To determine the effects of a whey protein compared to a control drink on systolic BP (SBP) and diastolic BP (DBP), and heart rate (HR) in healthy younger and older men, and to relate these effects to gastric emptying. DESIGN A pooled analyses of two randomized, double-blind, cross-over studies. SETTING Two acute clinical intervention studies with identical study design. PARTICIPANTS Nineteen older (age: 74 ± 1 years, body mass index: 26 ± 1 kg/m2 ) and 13 younger (23 ± 1 years, 24 ± 1 kg/m2 ) healthy men. INTERVENTION A 70 g/280 kcal whey-protein or control (water with diet cordial, ~2 kcal) drink (450 ml). MEASUREMENTS BP and HR were assessed with an automated device immediately before and at 3-min intervals after drink ingestion (0-180 min). Gastric emptying of the drinks was measured using 3D ultrasonography (0-180 min). RESULTS Older versus younger men exhibited a greater fall in SBP (-23 ± 2 vs -15 ± 2 mmHg, p = 0.001) after whey-protein versus control, as BP did not change after the two drinks in younger men (p > 0.05). The nadir in SBP occurred later in the older than younger men (114 ± 11 vs 62 ± 14 min; p

Cholecystectomy has been reported to be associated with increased risk of diabetes in cross-sectional studies. In the current study, we performed both cross-sectional and prospective analyses to examine the association between cholecystectomy and dysglycaemia in Chinese community-dwelling adults. A total of 1612 participants (n = 1564 without cholecystectomy and n = 48 with cholecystectomy) were evaluated for glycaemic status (according to the World Health Organization (WHO) 1999 criteria) and then followed up over ~3.2 years. Percent changes (Δ) in fasting blood glucose and HbA1c from baseline at the follow-up visit were calculated to define glycaemic control as stable (−10% ≤ Δ

Intestinal glucose absorption is integral to postprandial glucose homeostasis. Glucose absorption is dependent on a number of factors, including the exposure of carbohydrate to the mucosa of the upper gastrointestinal tract (determined particularly by the rates of gastric emptying and small intestinal transit), the digestion of complex carbohydrate into monosaccharides, and glucose sensing and transport by the intestinal mucosa. The absorption of glucose in the small intestine is not only a determinant of the appearance of exogenous glucose in the peripheral circulation, but is also coupled to the release of gastrointestinal hormones that in turn influence postprandial glucose metabolism through modulating gastrointestinal motor function, insulin and glucagon secretion, and subsequent energy intake. This review describes the physiology and pathophysiology of intestinal glucose absorption in health and type 2 diabetes, including its relevance to glucose tolerance and the management of postprandial hyperglycaemia.

The gastrointestinal tract is the key interface between the ingesta and the human body. There is wide recognition that the gastrointestinal response to nutrients or bioactive compounds, particularly the secretion of numerous hormones, is critical to the regulation of appetite, body weight and blood glucose. This concept has led to an increasing focus on “gut-based” strategies for the management of metabolic disorders, including type 2 diabetes and obesity. Understanding the underlying mechanisms and downstream effects of nutrient-gut interactions is fundamental to effective translation of this knowledge to clinical practice. To this end, an array of research tools and platforms have been developed to better understand the mechanisms of gut hormone secretion from enteroendocrine cells. This review discusses the evolution of in vitro and in vivo models and the integration of innovative techniques that will ultimately enable the development of novel therapies for metabolic diseases.

OBJECTIVE: Postprandial hypotension occurs frequently in older survivors of critical illness at 3 months after discharge. We aimed to determine whether postprandial hypotension and its predictors — gastric dysmotility and cardiovascular autonomic dysfunction — persist or resolve as older survivors of critical illness recover, and whether postprandial hypotension after intensive care unit (ICU) discharge is associated with adverse outcomes at 12 months. DESIGN: Prospective observational study. SETTING: Tertiary medical–surgical ICU. PARTICIPANTS: Older adults (aged > 65 years) who had been studied 3 months after ICU discharge and who returned for a follow-up study at 12 months after discharge. MAIN OUTCOME MEASURES: On both occasions after fasting overnight, participants consumed a 300 mL drink containing 75 g glucose, radiolabelled with 20 MBq 99mTcphytate. Blood pressure, heart rate, blood glucose concentration and gastric emptying rate were measured concurrently before and after ingestion of the drink. Falls, quality of life, hospitalisation and mortality rates were also quantified. RESULTS: Out of 35 older adults studied at 3 months, 22 returned for the follow-up study at 12 months. Postprandial hypotension was evident in 29% of participants (95% CI, 14–44%) at 3 months and 10% of participants (95% CI, 1–30%) at 12 months. Postprandial hypotension at 3 months was associated with a more than threefold increase in the risk of falls in the year after ICU discharge (relative risk, 3.7 [95% CI, 1.6–8.8]; P = 0.003). At 12 months, gastric emptying was normal (mean time taken for 50% of gastric contents to empty, 101.6 [SD, 33.3] min) and cardiovascular autonomic dysfunction prevalence was low (9% [95% CI, 1–29%]). CONCLUSIONS: In older adults who were evaluated 3 and 12 months after ICU discharge, postprandial hypotension at 3 months was associated with an increased risk of subsequent falls, but the prevalence of postprandial hypotension decreased with time.

Background Delayed gastric emptying is the leading cause of enteral feeding intolerance (EFI) in critical illness. This phase 2a study compared TAK‐954, a selective agonist of 5‐hydroxytryptamine type 4 receptors, with metoclopramide in critically ill patients with EFI (NCT01953081). Methods A blinded, double‐dummy trial was conducted in mechanically ventilated patients with EFI (>200 mL gastric residual volume within 24 hours before randomization). Patients were randomized to receive either 0.5 mg intravenous TAK‐954 over 1 hour then 0.9% saline injection 4 times/d (sham metoclopramide) or the active comparator 10 mg intravenous metoclopramide 4 times/d and a 1‐hour 0.9% saline infusion. After initial dosing, participants received a radiolabeled meal of liquid nutrient (Ensure; 106 kcal), and gastric emptying was measured (scintigraphy). Adverse events (AEs) were recorded from the time of consent through to day 5; serious AEs were collected to day 30. Results Thirteen patients (TAK‐954, n = 7; metoclopramide, n = 6) participated. Five patients in the TAK‐954 group and 4 in the metoclopramide group experienced AEs (2 and 3, respectively, were serious). All AEs except 1 (diarrhea in the metoclopramide group) were considered unrelated to study drug. Following treatment, a greater proportion of patients receiving TAK‐954 had normal gastric retention (

Refereed/Peer-reviewed Aims: The aim of this study was to evaluate the comparative effects of low-carbohydrate (LC), full-strength (FS), and low-alcohol (LA) beer on gastric emptying (GE), ethanol absorption, glycaemia and insulinaemia in health. Methods: Eight subjects (four male, four female; age: 20.4 +/- 0.4 years; BMI 22.7 +/- 0.4 kg/m(2)) had concurrent measurements of GE, plasma ethanol, blood glucose and plasma insulin for 180 min on three separate occasions after ingesting 600 mL of (i) FS beer (5.0% w/v, 246 kcal, 19.2 g carbohydrate), (ii) LC beer (4.6% w/v, 180 kcal, 5.4 g carbohydrate) and (iii) LA beer (2.6% w/v, 162 kcal, 17.4 g carbohydrate) labelled with 20 MBq 99mTc-calcium phytate, in random order. Results: There was no difference in the gastric 50% emptying time (T50) (FS: 89.0 +/- 13.5 min vs LC: 79.5 +/- 12.9 min vs LA: 74.6 +/- 12.4 min; P = .39). Plasma ethanol was less after LA than LC (P < .001) and FS (P < .001), with no difference between LC and FS (P = 1.0). There was an inverse relationship between plasma ethanol at 15 min and GE after LA (r = -0.87, P < .01) and a trend for inverse relationships after LC (r = -0.67, P = .07) and FS (r = -0.69, P = .06). The AUC 0-180 min for blood glucose was greater for LA than LC (P < .001), with no difference between LA and FS (P = .40) or LC and FS (P = 1.0). Conclusion: In healthy young subjects, GE of FS, LC and LA beer is comparable and a determinant of the plasma ethanol response.

The ingestion of dietary protein with, or before, carbohydrate may be a useful strategy to reduce postprandial hyperglycemia, but its effect in older people, who have an increased predisposition for type 2 diabetes, has not been clarified. Blood glucose, plasma insulin and glucagon concentrations were measured for 180 min following a drink containing either glucose (120 kcal), whey-protein (120 kcal), whey-protein plus glucose (240 kcal) or control (~2 kcal) in healthy younger (n = 10, 29 ± 2 years; 26.1 ± 0.4 kg/m2) and older men (n = 10, 78 ± 2 years; 27.3 ± 1.4 kg/m2). Mixed model analysis was used. In both age groups the co-ingestion of protein with glucose (i) markedly reduced the increase in blood glucose concentrations following glucose ingestion alone (p < 0.001) and (ii) had a synergistic effect on the increase in insulin concentrations (p = 0.002). Peak insulin concentrations after protein were unaffected by ageing, whereas insulin levels after glucose were lower in older than younger men (p < 0.05) and peak insulin concentrations were higher after glucose than protein in younger (p < 0.001) but not older men. Glucagon concentrations were unaffected by age. We conclude that the ability of whey-protein to reduce carbohydrate-induced postprandial hyperglycemia is retained in older men and that protein supplementation may be a useful strategy in the prevention and management of type 2 diabetes in older people.

Postprandial hypotension (PPH) occurs frequently in older people >65 years old. Protein-rich supplements, particularly whey protein (WP), are increasingly used by older people for various health benefits. We have reported that 70 g WP drinks cause significant, and in some cases marked, falls in blood pressure (BP) in older men. The effects of lower, more widely used, doses (~30 g) on systolic (SBP) and diastolic (DBP) blood pressure and heart rate (HR) are not known. In a randomized order, eight older men (age: 72 ± 1 years; body mass index (BMI): 25 ± 1 kg/m2) after overnight fast ingested a drink containing (i) a non-caloric control (~2 kcal), (ii) 30 g of whey protein (120 kcal; ‘WP30’), or (iii) 70 g of whey protein (280 kcal; ‘WP70’). The BP and HR were measured in this pilot study with an automated device before and at 3-min intervals for 180 min following drink ingestion. Drink condition effects were determined by repeated-measures ANOVA. The SBP decreased after both WP drinks compared to the control (p = 0.016), particularly between 120 and 180 min, with no difference in the effects of WP30 and WP70. The SBP decreased by ≥20 mmHg in more than 50% of people after both WP drinks (WP30: 63%; WP70: 75%) compared to 38% after the control. The maximum fall in the SBP occurred during the third hour, with the nadir occurring latest after WP70. The DBP decreased non-significantly by several mmHg more after the WP drinks than after the control. The maximum HR increases occurred during the third hour, with the greatest increase after WP70. The SBP decreased after both WP drinks compared to the control, with the effects most evident between 120 and 180 min. Accordingly, ingestion of even relatively modest protein loads in older men has the potential to cause PPH.

Introduction Breath tests utilising 13C-labelled substrates for the assessment of gastric emptying have been applied widely. Wagner-Nelson analysis is a pharmacokinetic model that can be utilised to generate a gastric emptying curve from the % 13CO2 measured in breath samples. We compared Wagner-Nelson analysis with (i) scintigraphy and (ii) conventional breath test modelling to quantify gastric emptying in type 2 diabetes. Methods Thirteen patients (age 68.1±1.5 years, body mass index 31.0±0.9 kg/m2, HbA1c 6.3±0.2%) consumed a mashed potato meal comprising 65 g powdered potato, 20 g glucose, 250 ml water, an egg yolk labelled with 100 μL 13C-octanoic acid and 20MBq 99mTc-calcium phytate. Scintigraphic data were acquired and breath samples collected for 4 hours after the meal. Gastric emptying curves were derived based on each technique; the 50% emptying time and intragastric retention at 60 min were also calculated. Results With Wagner-Nelson analysis, a Kel=0.60 (the elimination constant) best approximated the scintigraphic gastric emptying curve. There was a relationship between the T50 calculated with scintigraphy and by both Wagner-Nelson Kel=0.60 (r2=0.45, P Conclusion In type 2 diabetes, gastric emptying of a mashed potato meal measured using a 13C-octanoic acid breath test analysed with Wagner-Nelson Kel=0.60 closely reflects measurements obtained with scintigraphy, whereas, in absolute terms, the conventional breath test analysis does not.

Context The relationships of gastric emptying (GE) with the glycemic response at 120 minutes, glucagon-like peptide-1 (GLP-1), and insulin secretion following a glucose load in type 2 diabetes (T2D) are uncertain. Objective We evaluated the relationship of plasma glucose, GLP-1, and insulin secretion with GE of a 75-g oral glucose load in T2D. Design Single-center, cross-sectional, post hoc analysis. Setting Institutional research center. Participants 43 individuals with T2D age 65.6 ± 1.1 years, hemoglobin A1c 7.2 ± 1.0%, median duration of diabetes 5 years managed by diet and/or metformin. Intervention Participants consumed the glucose drink radiolabeled with 99mTc-phytate colloid following an overnight fast. GE (scintigraphy), plasma glucose, GLP-1, insulin, and C-peptide were measured between 0 and 180 minutes. Main Outcome Measures The relationships of the plasma glucose at 120 minutes, plasma GLP-1, and insulin secretion (calculated by Δinsulin0-30/ Δglucose0-30 and ΔC-peptide0-30/Δglucose0-30) with the rate of GE (scintigraphy) were evaluated. Results There were positive relationships of plasma glucose at 30 minutes (r = 0.56, P Conclusion In T2D, while insulin secretion is the dominant determinant of the 120-minute plasma glucose, GE also correlates. Given the relevance to interpreting the results of an oral glucose tolerance test, this relationship should be evaluated further. There appears to be no direct effect of GE on either GLP-1 or insulin secretion.

We read with interest the study by Rosenstock et al. (1), which demonstrates that in patients with type 2 diabetes managed on a basal-bolus insulin regimen, switching three prandial insulin injections for a long-acting glucagon-like peptide 1 receptor agonist (GLP-1RA), albiglutide, while maintaining the basal insulin, represents an effective strategy for optimizing glycemic control with reduced risks of hypoglycemia and weight gain along with increased convenience. In the cohort studied, baseline glycated hemoglobin levels were 7.8 ± 0.6% (albiglutide group) and 7.7 ± 0.6% (placebo group), indicating that in many participants, postprandial glycemic excursions were the dominant contributor of hyperglycemia. Achieving good glycemic control in those patients would, …

Context Both gastric emptying and the secretion of glucagon-like peptide-1 (GLP-1) are major determinants of postprandial glycemia in health and type 2 diabetes (T2D). GLP-1 secretion after a meal is dependent on the entry of nutrients into the small intestine, which, in turn, slows gastric emptying. Objective To define the relationship between gastric emptying and the GLP-1 response to both oral and small intestinal nutrients in subjects with and without T2D. Methods We evaluated: (i) the relationship between gastric emptying (breath test) and postprandial GLP-1 levels after a mashed potato meal in 73 individuals with T2D; (ii) inter-individual variations in GLP-1 response to (a) intraduodenal glucose (4 kcal/min) during euglycemia and hyperglycemia in 11 healthy and 12 T2D, subjects, (b) intraduodenal fat (2 kcal/min) in 15 T2D subjects, and (c) intraduodenal protein (3 kcal/min) in 10 healthy subjects; and (iii) the relationship between gastric emptying (breath test) of 75 g oral glucose and the GLP-1 response to intraduodenal glucose (4 kcal/min) in 21 subjects (9 healthy, 12 T2D). Results The GLP-1 response to the mashed potato meal was unrelated to the gastric half-emptying time (T50). The GLP-1 responses to intraduodenal glucose, fat, and protein varied substantially between individuals, but intra-individual variation to glucose was modest. The T50 of oral glucose was related directly to the GLP-1 response to intraduodenal glucose (r = 0.65, P = 0.002). Conclusion In a given individual, gastric emptying is not a determinant of the postprandial GLP-1 response. However, the intrinsic gastric emptying rate is determined in part by the responsiveness of GLP-1 to intestinal nutrients.

Glucose-dependent insulinotropic polypeptide (GIP) is released primarily from the proximal small intestine and glucagon-like peptide-1 (GLP-1) from the more distal small intestine and colon. Their relative importance to the incretin effect in health has been contentious in the past, although it now appears that GIP has the dominant role. It is uncertain whether there is a relationship between GIP and GLP-1 secretion. We aimed to evaluate the relationship between plasma GIP and GLP-1 responses to a 75-g oral glucose load in individuals with normal (NGT) and impaired glucose tolerance (IGT). One hundred healthy subjects had measurements of blood glucose, serum insulin, plasma GIP and GLP-1 concentrations for 240 min after a 300 mL drink containing 75 g glucose. Fifty had NGT and 41 IGT; 9 had type 2 diabetes and were excluded from analysis. In both groups, there were increases in plasma GIP and GLP-1 following the glucose drink, with no difference in the magnitude of the responses between t = 0–240 min. There was a weak relationship between the iAUC0–240 min for GIP and GLP-1 in the combined (r = 0.23, P = 0.015) and in the IGT (r = 0.34, P = 0.01), but not in the NGT (r = 0.15, P = 0.14) group. There is a weak relationship between oral glucose-induced GIP and GLP-1 secretions in non-diabetic subjects.