Growth hormone improves muscle protein metabolism and whole body nitrogen economy in man during a hyponitrogenous diet.

Healthy male volunteers (n = 12) were given a normocaloric hyponitrogenous diet for a conditioning period of 7 days. Thereafter they were blindly randomized to receive daily injections of methionyl recombinant human growth hormone (met-hGH) 0.06 IU/kg or saline during a second week of hyponitrogenous nutrition. The met-hGH group showed a lower urinary urea excretion and a lower serum concentration of urea as compared with the control group. In skeletal muscle, the polyribosome concentration, indicative of muscle protein synthesis, as well as the concentrations of glutamine, alanine, aspartate, serine, and threonine, decreased in the control group, whereas no such changes were seen in the met-hGH-treated group. Since provision of met-hGH prevented protein catabolism in muscle and improved whole body nitrogen economy, investigations of the possible beneficial effects of met-hGH to prevent skeletal muscle vast after surgical trauma are advocated.