Comparative study of the lipolytic potencies of pituitary-derived and biosynthetic human growth hormone in hypopituitary children.

Whether stimulation of lipolysis is an intrinsic property of the human growth hormone (hGH) molecule or is due to contaminants of pituitary origin is controversial. We compared the rises in plasma FFA levels 4 h after an im injection of 0.2 U/kg of either pituitary hGH (n = 5) or biosynthetic methionyl hGH (n = 32) to hypopituitary patients. In each patient, plasma FFA levels also were measured during a similar period of fasting alone, without hGH injection. Plasma FFA levels rose between 0800 and 1230 h in both subgroups of patients during fasting alone. Injection of either pituitary or biosynthetic methionyl hGH led to a greater increase in plasma FFA than that induced by fasting alone, and the percent increases over baseline plasma FFA levels induced by either pituitary or synthetic hGH were similar. Triceps skinfold thickness before and after 3 months of treatment with biosynthetic hGH in 20 patients diminished by a mean of 2.5 mm, a decrease similar to that reported with pituitary hGH. We conclude that the acute and chronic lipolytic effect of hGH in man is an intrinsic property of the hGH molecule.