Plasma growth hormone concentration after a single intramuscular injection of human growth hormone.

Abstract

Extract: We have investigated the concentration levels of growth hormone in plasma from six growth hormone-deficient patients who received human growth hormone (HGH) by intramusclar injection. The does varied 25 to 60 μg/kg body weight (38–92 mIU/kg body weight). An attempt also was made following intramuscular injection in two patients to amount of hormone excreted in the urine. Growth hormone was detected in plasma 15 min after HGH was administred and reached peak levels (65-154 ng/ml [mean 107.2±16.4 ng/ml SEM]) in the 2- or 4-h samples. In three patients, the concentraation of growth hormone had fallen to basal levels at 12 h; in all patients, 24 h after administration of HGH the lavels of growth hormone were essentially undetectable. No growth hormone was detected in any urine samples. The concentration of growth hormone in plasma observed after a single intramuscular injection differed markedly from the reported normal diurnal pattern. Speculation: These studies suggest that the continued presence of growth hormone in plasma is necessary for the promotion of growth in hypotuitary patients. Intermittent administration of growth hormone at weekly, biweekly or triweekly intervals may be associated with effects on the intracelluar protein synthetic mechanisms that persit the time of disappearance of growth hormone from the circulation.