Response of Normal and Hypophysectomized Rhesus Monkeys to Insulin. ∗

Abstract

It has been shown that dogs which are hypophysectomized show an increased sensitivity to insulin (Houssay and Magenta, 1 Geiling et al., 2 Chaikoff et al. 3 ). This method was used a number of years ago in a monkey to test for the completeness of the pituitary ablation Hartman et al. 4 ). We have tested the magnitude of the drop of blood sugar in completely and partially hypophysectomized and normal monkeys when insulin was injected after fasting. Since in half an hour after the insulin injection some of the operated animals collapsed the determinations could not be safely carried beyond that interval.

The procedure was as follows: After a 16-hour period of fasting a sample of blood was taken by cardiac puncture. Insulin (1/16 U./kilo) was then injected. Thirty minutes later a second blood sample from the heart was drawn, at which time in the collapsed hypophysectomized monkeys 50% glucose was injected into the heart to prevent death from hypoglycemia. In others 10% glucose was given subcutaneously.

The blood sugar was determined by the Somogyi modification of the Shaffer-Hartman method, reagent No. 1 being used. Each observation reported is the average value from 2 determinations on the same sample.