A Biphasic Glucose Response during an Oral Glucose Tolerance Test Is Associated with Greater Plasma Insulin and GLP-1 Responses and a Reduction in 1-Hour Glucose but Does Not Relate to the Rate of Gastric Emptying in Healthy, Older Adults

Published: 6 September 2023Background: The pattern of the plasma glucose response curve during an oral glucose tolerance test (OGTT) is of prognostic significance with “biphasic” when compared with “monophasic” patterns being associated with greater insulin sensitivity/secretion and a reduced risk of progression to diabetes. The relationships of the glucose response curves with gastric emptying and incretin hormone secretion are not known. Methods: Thirty-six adults (age > 65 years) without known diabetes consumed a 300 mL drink containing 75 g glucose and 150 mg C¹³-acetate at baseline and follow-up after 5.8 ± 0.1 years. Plasma glucose, glucagon-like peptide-1 (GLP-1), glucose independent insulinotropic polypeptide (GIP) and insulin were measured, and participants classified according to the pattern of their glucose response. Gastric emptying was measured on breath samples (stable isotope breath test). Results: At baseline, 22 participants had a “monophasic” and 14 a “biphasic” glucose response. The 1 h plasma glucose response curve was greater and the GLP-1 AUC₀_₁₂₀ min and insulin secretion lower in the monophasic group. There were no differences in gastric emptying, GIP or insulin sensitivity. At the follow-up, the 1 h glucose response curve was greater again, while GLP-1 AUC₀_₁₂₀ min was lower in the monophasic group. Conclusions: A biphasic curve is associated with a higher 60 min glucose response curve and increases in GLP-1, but no difference in either GIP or gastric emptying.Ryan J. Jalleh, Chinmay S. Marathe, Laurence G. Trahair, Karen L Jones, and Michael Horowit

Effect of gastric distension with concurrent small intestinal saline or glucose infusion on incretin hormone secretion in healthy individuals - a randomised, controlled, cross-over study.

Aims There is increasing interest in the use of intragastric balloons as a weight loss procedure, however, the underlying mechanism(s) remain unclear. In rodents, gastric distension has recently been shown to stimulate the secretion of the incretin hormone glucagon-like peptide-1 (GLP-1) substantially, but the effect of gastric distension on GLP-1 and the other incretin hormone, glucose-dependent insulinotropic polypeptide (GIP), in humans is not known. We conducted a randomized, controlled, crossover study to evaluate the effect of gastric distension, induced using a gastric 'barostat' on incretin hormones in healthy individuals Materials and methods Eight healthy participants (2 female, 6 male, mean age 69.3±1.2 years, and 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=0.99 for glucose infusion). Conclusion We conclude that gastric distension, either alone or during small intestinal glucose exposure, does not stimulate incretin hormone secretion significantly in healthy humans. This article is protected by copyright. All rights reserved.Ryan J. Jalleh, Laurence G. Trahair, Tongzhi Wu, Scott Standfield, Christine Feinle-Bisset, Christopher K. Rayner, Michael Horowitz, Karen L. Jone

Self-determined motivation in sport predicts anti-doping motivation and intention: A perspective from the trans-contextual model

Objectives: Motivation in sport has been frequently identified as a key factor of young athletes’ intention of doping in sport, but there has not been any attempt in scrutinizing the motivational mechanism involved. The present study applied the trans-contextual model of motivation to explain the relationship between motivation in a sport context and motivation and the social-cognitive factors (attitude, subjective norm, perceived behavioral control, and intention) from the theory of planned behavior (TPB) in an anti-doping context. Design: A cross-sectional survey was conducted. Methods: Questionnaire data was collected from 410 elite and sub-elite young athletes in Australia (Mean age [17.7 ± 3.9 yr], 55.4% male, Years in sport [9.1 ± 3.2]). We measured the key model variables of study in relation to sport motivation (Behavioral Regulation in Sport Questionnaire), and the motivation (adapted version of the Treatment Self-Regulation Questionnaire) and social cognitive patterns (the theory of planned behavior questionnaire) of doping avoidance. The data was analyzed by variance-based structural equation modeling with bootstrapping of 999 replications. Results: The goodness-of-fit of the hypothesized model was acceptable. The bootstrapped parameter estimates revealed that autonomous motivation and amotivation in sport were positively associated with the corresponding types of motivation for the avoidance of doping. Autonomous motivation, subjective norm, and perceived behavioral control in doping avoidance fully mediated the relationship between autonomous motivation in sport and intention for doping avoidance. Conclusions: The findings support the tenets of the trans-contextual model, and explain how motivation in sport is related to athletes’ motivation and intention with respect to anti-doping behaviors

Comparative effects of low-carbohydrate, full-strength and low-alcohol beer on gastric emptying, alcohol absorption, glycemia and insulinemia in health

First published: 05 March 2022Aims: The aim of this study was to evaluate the comparative effects of low-carbohy-drate (LC), full-strength (FS), and low-alcohol (LA) beer on gastric emptying (GE), eth-anol 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/m2) 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 minvs LC: 79.5 ± 12.9 minvs 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 at15 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 adeterminant of the plasma ethanol response.Julie E. Stevens, Ryan J. Jalleh, Laurence G. Trahair, Chinmay S. Marathe, Michael Horowitz, Karen L. Jone

Incretin hormone and glucoregulatory responses to nutrients in individuals with and without post-bariatric hypoglycaemia: a systematic review

Short Oral Discussion - SO 55 From low to high and back: the many faces of insulin therapy - Abstract#685R.J. Jalleh, M. Umapathysivam, J. Louise, M.P. Plummer, A. Deane, K.L. Jones, M. Horowit

Disparities in blood glucose and incretin responses to intraduodenal glucose infusion in healthy young males and females

Oral Presentation - OP 28 Desirable diets - Abstract #168T. Wu, C. Xie, W. Huang, Y. Sun, M. Horowitz, K.L. Jones, C.K. Rayne

Determinants of blood glucose concentrations after a high carbohydrate meal in type 2 diabetes: a multiple linear regression analysis

Oral Presentations - OP 28 Desirable diets- Abstract #166C. Xie, R.J. Jalleh, W. Huang, Y. Sun, K.L. Jones, M. Horowitz, C.K. Rayner, T. W

Determinants of blood glucose concentrations following a high carbohydrate meal in type 2 diabetes: A multiple linear regression analysis

Published online: March 07, 2023This study showed that in relatively well-controlled type 2 diabetes blood glucose levels after a high carbohydrate meal were associated positively with fasting blood glucose, but also positively with gastric emptying in the first hour and negatively with the increments in plasma glucagon-like peptide-1 (GLP-1) in the later postprandial phase.Cong Xie, Ryan J. Jalleh, Linda E. Watson, Weikun Huang, Yixuan Sun, Karen L. Jones, Michael Horowitz, Christopher K. Rayner, Tongzhi W

General Practitioners, Prevention and Alcohol - A powerful cocktail? Facilitators and inhibitors of practising preventive medicine in general and early intervention for alcohol in particular: A 12-nation key informant and general practitioner study

This study reports a qualitative investigation of the views of key informants (KIs) and general practitioners (GPs) on the nature and extent of preventive medicine and early alcohol intervention in general practice and the current barriers and potential facilitating factors that influence practice. Sixty-seven KIs and 126 GPs were interviewed in 12 countries. There was strong personal and professional support for GP-delivered preventive medicine in general and early intervention for alcohol problems in particular. Opinions differed on whether national health policies encouraged or discouraged GPs to do more preventive medicine. The two key areas identified for prevention were smoking and alcohol, although all but two countries thought that alcohol was the most difficult area for GPs to discuss with patients. KIs and GPs identified similar barriers and facilitating factors. The main barriers were time constraints, lack of financial reimbursement or incentives and insufficient training and education. The main facilitating factors were more societal concern about alcohol, proactive patients, more time, financial reimbursement and supportive government policy