EVIDENCE FOR STIMULATION OF INSULIN SECRETION BY GROWTH HORMONE IN THE RAT1

Based on the observation that only insulin will increase the concentration of glycogen in rat adipose tissue both in the presence and the absence of the pancreas, evidence for insulin secretion in response to growth hormone treat-ment was sought by measuring adipose tissue glycogen levels in fed intact and eviscerated rats. It had previously been shown that growth hormone had no influence on adipose tissue glycogen in 48-hour fasted rats, but the pancreas of these animals may be presumed to have been depleted of insulin. In fed rats given 2 ml. of 50 per cent glucose by stomach tube both insulin and growth hormone brought about significant increases in the glycogen content of the dorsal interscapular brown fat pad. Acutely eviscerated rats, which lack the pancreas, showed no accumulation of adipose tissue glycogen in response to a subcutaneous glucose load compared to intact controls unless given insulin.