INSULINOTROPIC ACTIONS OF INTRAVENOUS GLUCAGON-LIKE PEPTIDE-1 (GLP-1)[7-36-AMIDE] IN THE FASTING STATE IN HEALTHY-SUBJECTS

GLP-1 (7-36 amide) stimulates insulin and suppresses glucagon secretio n in normal subjects and may, in pharmacological doses, normalize hype rglycaemia in type 2 diabetic patients. It is not known whether such p harmacological doses can actually lower blood glucose to hypoglycaemic levels. Therefore, in seven normal fasting subjects, GLP-1 (7-36 amid e) was infused intravenously at 0.3, 0.9 and 2.7 pmol/kg per min for 3 0 min each. The plasma concentration of GLP-1 (7-36 amide) increased d ose-dependently, but insulin secretion (insulin, C-peptide) was stimul ated only marginally. Glucagon was slightly suppressed, and plasma glu cose was reduced, but not into the hypoglycaemic range. In conclusion, when plasma glucose concentrations are in the normal fasting range, G LP-1 (7-36 amide) is not able to stimulate insulin secretion to a degr ee that causes hypoglycaemia. This should limit the risk of hypoglycae mic responses when GLP-1 (7-36 amide) is administered in pharmacologic al doses to reduce hyperglycaemia in type 2 diabetic patients.