Response of Normal and Hypophysectomized Rhesus Monkeys to Insulin.

Abstract

It has been shown that doqs which are hypophvsectomized show an increaced senFitivitv t o insulin (Houssay and Mayenta,' Geilinq ef n1..' Chaikoff cf 0 1 .~) . This method was used a number of years aq'o in a nionkev to test for the completeness of the pituitary ablation Hartman et 0 1 .~) . W e have tested the maqnitude of the drop of Mood suqar in completelv and partially hypophysectomized and normal monkey 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 sulxutaneously. 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.It will be seen from Table I that hypophysectomized monkeys are very sensitive to insulin injections. The blood sugar values of normal animals decrease by 14% 30 minutes after 1/16 unit per kilo, while the completely hypophysectomized animal shows a blood * Aided b y a grant from the Committee for Research in Problems of Sex, the 1Houssay, B. A., and Magenta, M.

The effect of hypophysectomy on gastric motility in the dog.

“…Rouaaay and B3.genta (ll). &I1i th (12) and many others have found an inoreased sensitivity to insulin in the hypophysectomized animal. Reinbecker (13) showed in hypophy-.ectOBized dogs a low, fasting blood sugar.…”