Effect of cyproheptadine on human growth hormone secretion.

Abstract

ABSTRACT In order to determine whether or not a serotonergic mechanism is involved in the secretion of growth hormone, the effect of cyproheptadine, an antiserotonergic agent, on plasma human growth hormone (hGH) levels was studied in normal human subjects. Oral administration of 150 mg of 5-HTP, a precursor of serotonin, caused a rise in plasma hGH in 7 of 8 normal subjects tested, with peak hGH levels of 21.1 ± 4.7 ng/ml (mean ± sem). Plasma hGH response to 5-HTP was significantly suppressed by the intravenous infusion of cyproheptadine, an antiserotonergic agent (p < 0.01). Intravenous infusion of arginine caused a significant increase in plasma hGH, with peak hGH levels of 20.6 ± 4.9 ng/ml (mean ± sem). Plasma hGH response to arginine was significantly suppressed by the intravenous infusion of cyproheptadine (p < 0.05). These results suggest that the serotonergic mechanism is involved in the secretion of growth hormone in man.