Male rats with inherited insensitivity to androgen show reduced sexual behavior

Pseudohermaphroditic Stanley-Gumbreck male rats showed infrequent and incomplete copulatory responses to receptive females. Administration of testosterone propionate produced no increase in this behavior. Injections of estradiol and progesterone induced the pseudohermaphrodites to exhibit lordosis when mounted by stimulus males, but feminine responses were no more frequent than those of normal males given the same hormonal treatment. The hypothesis is suggested that early in development sufficient endogenous testis hormone is produced to cause normal desensitization of feminine behavioral mechanisms to estradiol, but that mechanisms for male behavior are not normally sensitized to testosterone.