Effect of growth hormone on pyruvic acid metabolism.

Abstract

The effect of bovine growth hormone on pyruvic acid metabolism was studied in normal dogs. The intravenous infusion of glucose (0.5 g/kg/30 min) into normal dogs results in a rise in the blood pyruvic acid concentration, followed by a return to control levels in 90 minutes. A growth hormone regimen (1 mg/kg/day) for 3–5 days produces an elevation in the pyruvic acid levels in the 17–20-hr-fasted dog. Administration of glucose at this time results in much higher blood pyruvate levels and a delayed return to control levels. The removal of glucose from the plasma is not impaired by this growth hormone regimen. The possibility that these findings reflect an inhibitory effect of growth hormone on pyruvic acid metabolism was investigated by determining the rate of removal of pyruvic acid from the blood after infusion of sodium pyruvate (0.3 g/kg/15 min) in normal dogs in the untreated state and while on a growth hormone regimen. The decline in pyruvate concentration from peak levels attained at the end of the infusion is markedly prolonged in the growth-hormone-treated animals, indicating impairment of pyruvate utilization. It is suggested that this action of growth hormone to impede removal of pyruvic acid from the blood is related to the fat-mobilizing effect of growth hormone.