EFFECT OF GROWTH-HORMONE TREATMENT ON POSTPRANDIAL PROTEIN-METABOLISMIN GROWTH HORMONE-DEFICIENT ADULTS

Growth hormone (GH) treatment of GH-deficient adults increases lean bo dy mass. To investigate this anabolic effect of GH, body composition a nd postabsorptive and postprandial protein metabolism mere measured in 12 GH-deficient adults randomized to placebo or GH treatment. Protein metabolism was measured after an infusion of [1-C-13]leucine before a nd after a standard meal at 0 and 2 mo. After 2 mo, there was an incre ase in lean body mass in the GH group (P < 0.05) but no change in the placebo group. In the postabsorptive state, there was increased nonoxi dative leucine disappearance (NOLD; a measure of protein synthesis) an d leucine metabolic clearance rate and decreased leucine oxidation in the GH group (P < 0.05) but no change in the placebo group. After the meal, there was an increase in NOLD and oxidation in all studies (P < 0.05), but the increase in NOLD, measured as area under the curve, was greater in the GH group (P < 0.05). This study clearly demonstrates f or the first time that the increase in protein synthesis in the postab sorptive state after GH treatment of GH-deficient adults is maintained in the postprandial state.