Effect of Growth Hormone on Cortisone-Induced Hyperinsulinemia and Reduction in Pancreatic Insulin in the Mouse

Effects of cortisone and growth hormone (GH) given singly and in combination were studied in black C57 and albino mice. Following injection of cortisone, after a latent period, serum immunoreactive insulin (IRI) rose progressively during 6–24 hr and remained at high levels, up to 15-fold the normal, for 8–10 days of treatment. Pancreatic IRI, after a delay of 2–6 hr, decreased to 63, 20 and 40 % of normal at 1, 3 and 8 days of treatment, respectively, in C57 mice. There was evidence, in albino mice also, of a tendency for pancreatic IRI to return to near normal late in the cortisone treatment. The early changes in 3 days occurred prior to rise in blood glucose. The results indicated that cortisone caused sustained enhancement of insulin secretion and that the rate of secretion was high relative to the rate of synthesis. Daily injections of bovine GH had no apparent effect on serum IRI or on pancreatic IRI during 10 days. However, when both hormones were injected concurrently, GH depressed the rise in serum IRI produced by cortisone during 3 days. Aldosterone, estradiol and testosterone injected for 3 days had little or no effect on IRI levels in serum and pancreas. Hydroxyprogesterone slightly increased serum IRI and pancreatic IRI. The interrelations of these hormones on activities of the pancreatic islets in various species are discussed. (Endocrinology87: 226, 1970)