Effect of chronic insulin administration on food intake and body weight in rats

Physiol Behav. 1991 Oct;50(4):801-6. doi: 10.1016/0031-9384(91)90021-f.


Insulin was chronically administered to rats to determine its effect on the daily changes in food intake and body weight. Animals received regular insulin via 14-day osmotic minipumps in doses of 0.0, 0.5, 1.0, 3.0, and 5.0 IU/day treated either with (+GLU) or without glutamic acid (-GLU). Previous studies have shown that glutamic acid prevents insulin aggregation in the minipumps to provide a more stable flow rate. Food intake and body weights were measured each day of treatment. Chronic insulin treatment was ineffective in promoting changes in animals receiving any dose of insulin except the highest dose. Animals receiving 5.0 IU/day insulin + GLU experienced a transient hyperphagia and weight gain followed by a suppression in food intake and body weight by Day 4 of treatment. Effects were attenuated in animals receiving insulin -GLU. Plasma insulin concentrations on Day 14 were similar for all doses, suggesting a compensation took place either in insulin degradation or endogenous insulin production. Results indicate that glutamic acid treatment enhances the effects of chronic insulin administration via osmotic minipumps.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blood Glucose / metabolism*
  • Body Composition / drug effects
  • Body Composition / physiology
  • Body Weight / drug effects
  • Body Weight / physiology*
  • Dose-Response Relationship, Drug
  • Energy Metabolism / drug effects
  • Energy Metabolism / physiology*
  • Feeding Behavior / drug effects
  • Feeding Behavior / physiology*
  • Glutamates / pharmacology
  • Glutamates / physiology
  • Glutamic Acid
  • Insulin / pharmacology
  • Insulin / physiology*
  • Male
  • Rats
  • Rats, Inbred Strains


  • Blood Glucose
  • Glutamates
  • Insulin
  • Glutamic Acid