Evidence for central nervous system (CNS) involvement in inhibition of luteinizing hormone (LH) release by dopamine receptor stimulation.

A pharmacologic study using 2-Br-alpha-ergocryptine (CB-154), a dopamine (DA) receptor agonist, the pimozide, a specific DA receptor antagonist, was undertaken to evaluate effects of manipulation of the DA system on plasma LH levels and on the ability of the pituitary to release LH following LHRH stimulation. Intraveneous administration of CB-154 lowered plasma LH levels in ovariectomized rats. Prior treatment with pimozide blocked the effect of CB-154, supporting dopaminergic system mediation in the observed response. Inhibition of LH release by pharmacologic stimulation of DA receptors did not appear to occur at the level of the pituitary, as pituitary release of LH following LHRH was not altered in CB-154 treated rats.