Exendin-4, a GLP-1 Receptor Agonist, Modulates the Effect of Macronutrients on Food Intake by Rats
Abstract
The hypothesis that peripheral GLP-1 modulates the effect of macronutrients on food intake in rats was tested by administration of its agonist, exendin-4. The effect of exendin-4 on food intake suppression and blood glucose after carbohydrate, fat and protein preloads was measured. Exendin-4 reduced the effect of glucose preloads on food intake only during the first 30 min ( P = 0.01) of feeding, but had a more prolonged effect when given with corn oil ( P < 0.01 at 0–0.5 h and 0–1 h, P = 0.055 at 0–2 h, and P = 0.07 at 0–3 h) and whey ( P < 0.05 at 0–1 h, P = 0.06 at 0–2 h, and P = 0.07 at 0–3 h) preloads. Blood glucose measured over 2 h was reduced at 15 min when given with glucose ( P < 0.01), unchanged when given with corn oil and increased at 60 and 120 min when given with whey ( P < 0.01). Thus, the effect of exendin-4 on the feeding response depended on the composition of the macronutrient preloads and seems to be independent of blood glucose concentrations. KEY WORDS: • agonist • blood glucose • food intake • gut peptide • intraperitoneal administration • rats