Stress, Insulin Antagonist and Transient Diabetes Mellitus in the Rat

Abstract

The diabetogenic activity of growth hormone (GH) was studied through the production of an insulin antagonist in the plasma of normal rat. This antagonist, called alpha₂-inhibitor, has an inhibitory activity on the glucose uptake by isolated testis, epididymal fat and hemidiaphragm of normal rat, is GH-dependent and has been identified with a fraction of plasma alpha₂-glycoproteins.

The functional dependence of alpha₂-inhibitor from GH was studied in two conditions: a) post-stress hypersecretion of GH; and, b) post-administration of rat GH, without stress. The results showed the production of the alpha₂-inhibitor in both conditions, 3 hours post-stress or GH administration. Since the normal intact Sprague-Dawley male rat has no plasma alpha₂-inhibitor, it is concluded that it was induced by the stress.

In the 80% pancreatectomized rat, the systemic stress produced, together with the increment of plasma alpha₂-inhibitor, a transient state of diabetes mellitus that lasted 4 hours and attained the peak 2 hours post-stress.

Key words

Insulin Antagonist - Stress - Diabetes - Growth Hormone - Partially Pancreatectomized Rat