GLP-1's Effects Similar in Those With, Without Diabetes
Study examines effect of endogenous glucagon-like peptide-1 on insulin release
WEDNESDAY, June 16 (HealthDay News) -- In patients with well-controlled type 2 diabetes, the effects of enteral stimuli and endogenous glucagon-like peptide-1 (GLP-1) on insulin release are similar to those in individuals without diabetes, according to research published in the June issue of Diabetes.
Marzieh Salehi, M.D., of the University of Cincinnati, and colleagues analyzed data from 12 patients with well-controlled type 2 diabetes and eight matched control subjects. All received a glucose infusion to maintain blood glucose at 5 mmol/L above fasting levels and ate a breakfast containing D-xylose. The studies were done once with an infusion of exendin-(9-39) (Ex-9) -- a GLP-1 receptor antagonist -- and once with saline.
The researchers found that the diabetes and non-diabetes groups had a similar increase in insulin secretion after the meal (44 and 47 percent, respectively). Blocking GLP-1's action suppressed postprandial insulin secretion to a similar degree in both groups (25 versus 27 percent). Ex-9 reduced the insulin response to intravenous glucose in both groups (25 and 26 percent, respectively), even when plasma levels of GLP-1 weren't detectable.
"In summary, we report here that administration of Ex-9 reduces insulin secretion proportionately in response to intravenous glucose and enteral stimuli, and that this effect is similar in diabetic and nondiabetic subjects. These findings indicate that the effect of endogenous GLP-1 on postprandial insulin release is preserved in patients with well-controlled type 2 diabetes," the authors conclude.