The Rate of Intestinal Glucose Absorption Is Correlated with Plasma Glucose-Dependent Insulinotropic Polypeptide Concentrations in Healthy Men

Abstract

Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) both play a role in the control of glucose homeostasis, and GIP is implicated in the regulation of energy storage. The capacity of carbohydrates to induce secretion of these incretin hormones could be one of the factors determining the metabolic quality of different types of carbohydrates. We analyzed the correlation between the rate of intestinal absorption of (starch-derived) glucose and plasma concentrations of GLP-1 and GIP after ingestion of glucose and starchy foods with a different content of rapidly and slowly available glucose. In a crossover study, glucose, insulin, GLP-1, and GIP concentrations were monitored for 6 h after consumption of glucose, uncooked cornstarch (UCCS) or corn pasta in 7 healthy men. All test meals were naturally labeled with 13C. Using a primed, continuous D-[6,6-2H2]glucose infusion, the rate of appearance of exogenous glucose (RaEx) was estimated, reflecting the rate of intestinal glucose absorption. GLP-1 concentrations increased significantly from 180 to 300 min after ingestion of UCCS, the starch product with a high content of slowly available glucose. A high GIP response in the early postprandial phase (15-90 min) occurred after consumption of glucose. There was a strong positive within-subject correlation between RaEx and GIP concentrations (r = 0.73, P < 0.01) across the test meals. Rapidly and slowly digestible carbohydrates differ considerably in their ability to stimulate secretion of incretin hormones; the metabolic consequences of such differences warrant exploration.

Separate Impact of Obesity and Glucose Tolerance on the Incretin Effect in Normal Subjects and Type 2 Diabetic Patients

“…The positive relation of GLP-1 response to oral glucose appearance (also found by others [23]) is best explained by the fact that the rate of glucose transfer across the intestinal mucosa is a quantitative determinant of the release of gastrointestinal hormones (43). This conclusion is indirectly supported by the observation that dipeptidylpeptidase intravenous inhibitors, which cause modest increments in endogenous GLP-1 levels, have been shown not to alter gastric emptying (44), whereas the use of GLP-1 analogs delays gastric emptying (45).…”

Dietary Resistant Starch Reduces Levels of Glucose-Dependent Insulinotropic Polypeptide mRNA along the Jejunum-Ileum in Both Normal and Type 2 Diabetic Rats

“…[8][9][10] Additionally, the circulating GIP levels were lower in humans that had ingested starch than in those that had ingested glucose. 17) Taking our results and these earlier reports together, the delay in glucose absorption caused by starch being degraded slowly in the lumen should lead to a reduction in GIP gene expression. It is still unknown which signal altered the GIP mRNA levels in the rats fed on the diet with RS.…”

Collapse and reorganization of a food web of Mwanza Gulf, Lake Victoria

“…In our studies, 13 Cisotopic enrichment is usually determined with GC/C/IRMS, requiring derivatization of plasma samples prior to analysis (21)(22)(23)(24). Since the introduction of the LC interface for IRMS by Krummen et al (25), several studies showed the power and accuracy of this method in many disciplines (26)(27)(28)(29)(30).…”