The Effect of Pimozide, a Dopamine Antagonist, on Pituitary Gonadotrophic Function in the Rat

Summary. Injection of pimozide reduced compensatory ovarian hypertrophy and raised pituitary LH content in hemispayed cyclic and androgenized female rats. Pimozide inhibited spontaneous and induced ovulation and markedly reduced the rise in serum LH during the afternoon of pro-oestrus. Pimozide failed to reduce serum LH in male rats and caused no apparent delay in sexual maturation in males or females. The results suggest that the drug suppresses the ovulatory release of LH, presumably by antagonizing hypothalamic dopamine. The drug appears to have less striking effects on the tonic secretion of FSH and LH.