Differential effects of a dopaminergic drug (piribedil) on pituitary hormone release in normal men and women
Abstract. Six normal women, in the follicular phase of their menstrual cycle, and 6 normal men received orally 40, 60 and 100 mg doses of piribedil, a dopamine receptor agonist, or placebo. The effects of piribedil on anterior pituitary hormone release was evaluated. In normal women a dose-related decrease in Prl levels was observed, while in men the Prl decrement was not related to the dose employed. In women an increase in serum hGH occurred after administration of the lowest (40 mg) dose of piribedil. In normal men, on the contrary, a modest hGH stimulation was present after administration of all doses of the drug. No consistent changes in serum TSH, LH and FSH concentrations were observed and no side effects were reported. The results from this study indicate that piribedil can exert differential effects on hypophyseal trophic hormone release and that these effects are sex-related. It is possible that the differences observed in men and women after the administration of piribedil are due to a different endogenous dopaminergic tone, induced by the different sexual steroid environment.