During the reproductive season in August, we administered to adult male and female Carp an LHRH analog (LHRH-A = D-trp6EA-LHRH) (50 micrograms/kg) alone or in association with pimozide, a dopamine inhibitor (10 mg/kg). LHRH-A caused the circulating portal level of gonadotropin to rise significantly in males and less in females. Spermiation was stimulated in the males and oocyte maturation in females but there was no ovulation. An infection of pimozide and then of LHRH-A 6 h later significantly increased c-GTH secretion and spermiation more than LHRH-A given alone, and induced ovulation in the females.