Journal of Endocrinological Investigation

, Volume 10, Issue 3, pp 325–327 | Cite as

Reduction of glycogen stores in a rat model of chronic hyperinsulinism

  • P. Masiello
  • E. Bergamini
Short Communication


To assess a suitable model for the study of the mechanisms of development of insulin resistance in vivo, liver and muscle glycogen levels (as a metabolic index of tissue insulin sensitivity) were investigated in rats with functioning islet cell adenomas induced by streptozotocin and nicotinamide. These rats have basal moderate hyperinsulinemia and hypoglycemia and show a remarkable increase in insulin secretion after glucose administration. Plasma glucagon concentrations are normal. Nevertheless, in tumor-bearing rats, a reduction of tissue glycogen stores occurs, related to plasma glucose concentrations, and liver glycogen fails to increase even after a glucose load. The lack of excess fat in tumor-bearing rats also suggests a certain insulin insensitivity of the adipose tissue and distinguishes this model of chronic hyperinsulinism from other reported models, such as genetically obese animals.


Hyperinsulinism islet cell tumor rat glycogen insulin resistance 


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Copyright information

© Italian Society of Endocrinology (SIE) 1987

Authors and Affiliations

  • P. Masiello
    • 1
  • E. Bergamini
    • 1
  1. 1.Istituto di Patologia Generale, Scuola MedicaUniversity of PisaPisaItaly

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