Suppression of food intake by intragastric glucose in rats with impaired glucose tolerance

Abstract

Three experiments were performed to examine the relationship between impaired glucose tolerance and food intake. In the first experiment, normal rats that were given long-term insulin treatment, which was then withdrawn, ate less than controls when refed after food deprivation. Despite reduced intakes, rats previously treated with insulin became more hyperglycemic than controls during refeeding. In the second experiment, intragastric glucose injections reduced food intakes to a similar degree in control rats and in rats experiencing insulin withdrawal even though glucose loading produced a much greater increase in plasma glucose level in previously insulin-treated rats. In the third experiment, intragastric loads of a glucose polymer, Polycose, reduced food intake to the same degree in normal rats and in streptozotocin-diabetic rats both two and sixteen days after insulin withdrawal when diabetic rats were, respectively, hypo- and hyperphagic. The results show that impaired glucose tolerance does not appreciably alter the suppressive effects of glucose loading on food intake. Other effects of glucose administration, besides those on insulin-dependent glucose utilization, appear to reduce food intake after glucose loading.