Plasma LH and FSH Levels in the Androgen Insensitive Pseudohermaphroditic Rat: Responses to Steroid Administration1

Abstract

Plasma LH and FSH levels were determined in androgen insensitive Stanley- Gumbreck male pseudohermaphroditic (Ps) rats. Plasma LH levels in intact Ps animals were 4- fold higher than in normal (Nl) male litter mates, while FSH levels were equal. The elevated LH levels were correlated with pituitary “castration cells” and increased Leydig cell 3β-hydroxysteroid dehydrogenase activity. Administration of testosterone enanthate 6 mg daily for 12 days, to castrated animals, produced 50% and 98% suppression of plasma LH in Ps and Nl rats, respectively. By contrast, estradiol produced a similar decrease of plasma LH in both groups. The changes of plasma FSH concentrations during sex steroid administration were qualitatively similar to those of LH. Testosterone enanthate administration produced a marked increase in preputial gland weight in Nl animals and a small but detectable increase in Ps rats. This observation, along with the LH suppression, indicates that the androgen insensitivity in these animals is relat...