The effects of testosterone on insulin sensitivity in male rats

Acta Physiol Scand. 1992 Dec;146(4):505-10. doi: 10.1111/j.1748-1716.1992.tb09452.x.


In order to examine the effects of testosterone (T) on insulin sensitivity, male rats were castrated or sham-operated, and exposed to low or high doses of T to substitute normal or to produce high serum T concentrations. Insulin sensitivity was followed by euglycaemic, hyperinsulinaemic glucose clamp measurements. An index of insulin-stimulated glucose transport was obtained in the white gastrocnemius (WG), extensor digitorum longus (EDL), red gastrocnemius (RG) and soleus (SOL) muscles after a bolus dose of [2-3H]deoxyglucose (2-DOG) when steady state was obtained in the clamp measurements. Glycogen synthesis was followed similarly with [U-14C]glucose as a labelled precursor after isolation of glycogen in the muscles mentioned, and in the liver. Castration and high T were followed by a marked insulin resistance in the clamp measurements. This was paralleled by a diminished insulin stimulation of glucose incorporation into glycogen down to about 50% of control values, apparently equally pronounced in all muscles but not found in liver glycogen synthesis. 2-DOG uptake was diminished by castration in the WG and RG muscles but was unaffected by high doses of T. Substitution of castrated rats with a low dose of T, restoring their serum T concentrations to the normal range, completely abolished these perturbations of insulin sensitivity. It is concluded that T is an important regulator of muscular insulin sensitivity, which seems to be highest in a 'window' of normal serum T concentrations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Corticosterone / blood
  • Deoxyglucose / metabolism
  • Glucose / metabolism
  • Glycogen / biosynthesis
  • Insulin Resistance / physiology*
  • Kinetics
  • Male
  • Muscles / drug effects
  • Muscles / metabolism
  • Orchiectomy
  • Rats
  • Rats, Sprague-Dawley
  • Testis / physiology
  • Testosterone / blood
  • Testosterone / pharmacology*


  • Testosterone
  • Glycogen
  • Deoxyglucose
  • Glucose
  • Corticosterone