Our objective was to examine the effect of biosynthetic human growth hormone (BSHGH) on protein and energy metabolism in patients on full intravenous nutrition (IVN). Fifteen patients who had been established on IVN were allocated at random to receive either BSHGH (0.1 mg/kg/day) or placebo daily for 7 days. All patients received the same feeding regimen which contaminated 14 gN, 1000 kcal of glucose and 1000 kcal of fat (Intralipid) daily. The mean nitrogen balance for days 4 to 7 was significantly more positive with BSHGH (7.0 +/- 0.6 gN/day) than with placebo (4.4 +/- 0.7 gN/day). The BSHGH group were lighter (53 +/- 4.6 kg body weight) than controls (68 +/- 5.1 kg), but the difference was not significant. Resting energy expenditure (expressed as percentage of day 1) increased throughout the study in patients receiving BSHGH (day 7, 120.8 +/- 5.5%), whereas in patients receiving placebo it remained stable (day 7, 98.9 +/- 2.7%). The nonprotein respiratory quotients were similar for BSHGH (mean days 4-7, 0.94 +/- 0.04) and placebo (mean days 4-7, 0.93 +/- 0.01) (p greater than 0.05). This study demonstrates more positive nitrogen balance, which may in part be due to different substrate loads, and an increase in energy expenditure in patients receiving BSHGH.