Effects of Insulin Preparations on Titrated Sucrose Regulation

Abstract

Albino rats were conditioned on a titration schedule of reinforcement which enabled the animals to adjust the sucrose concentration of food pellets. Concentrations of 90%, 70%, 50%, 30% and 10% sucrose were decreased by 20% every 30 sec. unless the animal emitted 1 of 2 concurrent operants, which reversed the process. Preparations of globin, protamine, and regular insulins were administered via the intraperitoneal route in small doses, on separate sessions, when steady states on the titration schedule were observed. Regular insulin had the strongest effect in producing higher titration and pellet rates and greater sucrose consumption.