Insulinotropic Action of Glucagonlike Peptide-I-(7–37) in Diabetic and Nondiabetic Subjects

Abstract

Objective Whether glucagonlike peptide-I-(7–37) (GLP-I-[7–37]), a naturally occurring intestinal peptide, is insulinotropic in nondiabetic and non-insulindependent (type II) diabetic subjects. Research Design and Methods GLP-I-(7–37) or saline placebo was infused (1–5 ng · kg⁻¹ · min⁻¹ for 30 min) in 4 nondiabetic and 11 type II diabetic subjects in the fasting and prandial state. Glucose, insulin, and GLP-I-(7–37) levels were measured. Results GLP-I-(7–37) infusion resulted in a 3- to 10-fold increase in peak insulin levels and in insulin area under the curve in nondiabetic and diabetic subjects. In diabetic subjects, infusion concurrent with a standard meal eliminated the postprandial glucose excursion for 60 min after the meal. Insulin-releasing potency of GLP-I-(7-37) was attenuated at decreased glucose levels. Conclusions GLP-I-(7–37) has potent insulinotropic effects in nondiabetic and diabetic subjects. Whether GLP-I-(7–37) is useful as a therapeutic medication in type II diabetes requires further investigation.