INSULINOTROPIC ACTION OF GLUCAGON-LIKE PEPTIDE-I-(7-37) IN DIABETIC AND NONDIABETIC SUBJECTS

OBJECTIVE - Whether glucagonlike peptide-I-(7-37) (GLP-I-[7-37]), a naturally occurring intestinal peptide, is insulinotropic in nondiabetic and non-insulin-dependent (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.