Secretion and Dipeptidyl Peptidase-4-Mediated Metabolism of Incretin Hormones after a Mixed Meal or Glucose Ingestion in Obese Compared to Lean, Nondiabetic Men

Abstract

1) Release and degradation of the two incretin hormones show dissociated changes in obesity: GLP-1 but not GIP secretion is lower after meal ingestion and oral glucose, whereas GIP but not GLP-1 metabolism is increased after meal ingestion. 2) Increased plasma DPP-4 activity in obesity is not associated with a generalized augmented incretin hormone metabolism.

Incretin secretion and serum DPP-IV activity in Korean patients with type 2 diabetes

“…Therefore, this phenomenon may be attributable to ethnic differences. In some Western studies, obesity was associated with GLP-1 secretion defects [2,4,14]. However, consistent with other Asian studies, we did not find an association between BMI and GLP-1 secretion [8,9].…”

“…Serum DPP-IV activity was associated with HbAlc, but not with intact GLP-1 secretion. Our results are supported by recent studies that show serum DPP-IV activity levels may be affected by long-term glycemic levels, but do not reflect the degree of in vivo incretin hormone degradation by DPP-IV [7,14]. Therefore, measurements of serum DPP-IV activity cannot be used to predict in vivo incretin degradation.…”

Metabolic and Hormonal Response to a Feed‐challenge Test in Lean and Overweight Dogs

“…The sandwich‐ELISA uses N‐terminal for capture and C‐terminal for detection, making cross reactivity to pro‐glucagon derived peptides, a common problem with previous assays, less likely 33, 3418 In response to the high‐fat mixed‐meal, glucagon concentration increased significantly from 1 hour postprandially, and the overall response was similar to that observed in people after a mixed‐meal 35, 36. In people, the rapid increase in glucagon concentration after ingestion of pure fat diminishes when carbohydrates are added to the food,37 whereas ingestion of pure glucose leads to decreasing glucagon concentrations 36.…”

Effects of a high-fat meal on postprandial incretin responses, appetite scores and ad libitum energy intake in women with obesity

“…Other studies that used infusions of exogenous GLP-1 at low rates (to reflect physiological postprandial concentrations) did also not detect any influence of GLP-1 on food intake (2,34). All these results suggest that, in physiological conditions, changes in GLP-1 along and after a meal do not significantly impact appetite regulation and subsequent energy intake in the short term, especially in individuals with obesity who seem to have an attenuated GLP-1 response during meals (5)(6)(7).…”

“…Only about 10-15% of GLP-1 secreted reaches peripheral tissues and pancreatic β cells (35). It is important to consider the larger activity of DPP-IV verified in obesity; this degrades GLP-1 more precociously, thereby limiting its appetite-regulating actions in this condition (6,7).…”