Early and Late Effects of Growth Hormone on the Metabolism of Glucose in Adipose Tissue

Abstract

The effect of growth hormone on the metabolism of glucose by adipose tissue was measured in vitro at various intervals after the administration of growth hormone (50 μg) in vivo to hypophysectomized rats. Thirty min after growth hormone administration U-¹⁴C glucose uptake, oxidation to CO₂, and incorporation into fatty acids were doubled. This effect of growth hormone was reduced 1 hr after administration, and at 3½ hr opposite effects were observed: glucose uptake and fatty acid synthesis were reduced. Twentyfour hr after growth hormone, the metabolism of glucose was still inhibited, as evidenced by decreased uptake and oxidation of glucose and incorporation of its carbons into fatty acids. Three and one half hr after growth hormone injection the response of adipose tissue to growth hormone added in vitro was abolished. Administration of actinomycin D to these rats 1-2 hr before growth hormone was injected reversed the inhibitory effects of growth hormone on the metabolism of glucose and the response to growth hormone in vitro. (Endocrinology76: 1134, 1965)