Insulin secretory responses to rising and falling glucose concentrations are delayed in subjects with impaired glucose tolerance
Related Experiment Video
Updated: Jul 20, 2026

Characterization of Metabolic Status in Nonhuman Primates with the Intravenous Glucose Tolerance Test
Published on: November 13, 2016
D A Ehrmann1, E Breda, M K Cavaghan
1Department of Medicine, Section of Endocrinology, The University of Chicago Pritzker School of Medicine, Chicago, Illinois 60637, USA. dehrmann@medicine.bsd.uchicago.edu
Aims/Hypothesis:
We hypothesized that beta-cell responses to changes in glucose would not be normal in subjects with impaired glucose tolerance (IGT).
Methods:
Three groups of 6 subjects were studied: normal weight with normal glucose tolerance (control subjects); obese with normal glucose tolerance (Obese-NGT); and obese with IGT (Obese-IGT). All subjects had a graded glucose infusion protocol to increase (step-up) and then decrease (step-down) plasma glucose. We obtained average insulin-secretion rates (ISR) over the glucose range common to all three groups during step-up and step-down phases, minimal model indices of beta-cell function (f(b), f(d), f(s), T(up), T(down) ), and insulin sensitivity (Si).
Results:
ISR differed significantly between step-up and -down phases only in Obese-IGT individuals. Basal (f(b)) and stimulated (f(d), f(s)) beta-cell sensitivity to glucose were similar in the three groups. Delays between glucose stimulus and beta-cell response during both step-up (T(up)) and -down (T(down)) phases were higher in Obese-IGT compared to Controls and Obese-NGT individuals. The product ISR x Si (10(-5.)min(-2) x l) was lower in Obese-IGT compared to Controls, both during step-up (919 +/- 851 vs 3192 +/- 1185, p < 0.05) and step-down (1455 +/- 1203 vs 3625 +/- 691, p < 0.05) phases. Consistently, the product f(s) x Si (10(-14.)min(-2). pmol(-1) x l) was lower in Obese-IGT than in control subjects (27.6 +/- 25.4 vs 103.1 +/- 20.2, p < 0.05).
Conclusion/Interpretation:
Subjects with IGT are not able to secrete insulin to compensate adequately for insulin resistance. They also show delays in the timing of the beta-cell response to glucose when glucose levels are either rising or falling.
More Related Videos
08:03Glucose Uptake Measurement and Response to Insulin Stimulation in In Vitro Cultured Human Primary Myotubes
Published on: June 25, 2017
08:13Study of In Vivo Glucose Metabolism in High-fat Diet-fed Mice Using Oral Glucose Tolerance Test (OGTT) and Insulin Tolerance Test (ITT)
Published on: January 7, 2018
Related Concept Videos
Hormones Regulating Blood Glucose
In addition to accelerating glucose uptake and utilization, insulin has...
Glucose Homeostasis: Pancreatic Islets and Insulin Secretion
Insulin and C-peptide are co-secreted in...
Oral Hypoglycemic Agents: Glinides
Hypoglycemia and Glucagon
Type II Diabetes II: Pathophysiology
Hypoglycemia