Dopaminergic factors in human prolactin regulation: a pituitary model for the study of a neuroendocrine system in man.

This study in normal male subjects further investigates the effects of dopaminergic-antidopaminergic interactions as manifested by the prolactin response to dopamine and neuroleptic drugs. Incremental doses of dopamine hydrochloride (4 microgram/min, 15 microgram/min, 60 microgram/min, 300 microgram/min) were infused at a constant rate over 90-120 min after a fixed dose of a neuroleptic drug (sufficient for about half of the maximal prolactin response) had been given IV. A dose of dopamine in the order of 15-60 microgram/min appeared to match the "loss" of endogenous dopaminergic inhibition due to the antidopaminergic effect of the neuroleptic drug. The lactotrophic cells of the pituitary gland are suggested to serve as a model in man for the study of some basic neurohormonal mechanisms.