Stimulus for Glucagon-Like Peptide 1 Secretion in Rats.

Blood concentration of glucagon-like peptide-1 (GLP-1) increased 5 min after per os administration of water, sodium chloride solution, or glucose solution. Changes in blood osmolality or blood glucose level did not stimulate GLP-1 release. A method of short-term increase in the gastric capacity in rats using an inflating balloon attached to the Foley catheter was developed in order to test the hypothesis that excitation of the upper gastrointestinal tract receptors is a primary signal for the GLP-1 secretion during oral intake of the substances. Mechanical gastric distension in rats caused elevation of the blood GLP-1 concentration which was comparable to the effects of oral administration of water, sodium chloride, and glucose solutions.