Sexual reversibility in neonatally castrated male rats.

Abstract

24 male rats, castrated on the day of birth, were administered male or female hormones starting at 100 days of age and tested for male or female mating. Males initially administered testosterone mounted females. Males initially administered estrogen and progesterone exhibited lordosis when mounted by males. When the hormone conditions were reversed for these groups, Ss displayed behavior appropriate to the hormone given. Additional Ss were given male or female hormones but not allowed to mate. When the hormone treatments were reversed for these Ss, behavior appropriate to the hormone given was Induced. Thus the male rat castrated at birth is not fixated as male or female in adulthood by either hormone treatment or sexual experience.