Abstract
Gastric inhibitory polypeptide (GIP) release into the portal vein in response to duodenal instillation of amino acid (AA) solutions in doses of 1.379, 2.758, 5.516, and 11.032 mmol/kg body weight was studied in an acute male Wistar rat preparation. A rapid dose-dependent, and significant rise in portal vein plasma GIP was found in response to increasing duodenal AA loads, and this could be described by Michaelis-Menten kinetics.