An electron microscopical study on effects of synthesized estrogen on the anterior pituitary of male mice

Effects of natural estrogen and synthetic nonsteroidal estrogens on the finestructure of the anterior pituitary cells of the male mouse were studied. As estrogeniccompounds, estradiol-17 p, hexestrol, and two hexestrol difatty acid esters (hexestroldicaproate and hexestrol dicaprylate) were used. Seven days after injection with a singledose of 100, pg per adult male mouse, the hexestrol difatty acid esters induced strikingmorphological alterations in the gonadotrophic cells, including LTII cells. LTH cells werehypertrophied drastically and LIT cells relatively, while FSH cells exhibited. an atrophicappearance.In order to confirm the suppressive effect of the estrogens on FSH cells, male mice wereorchidectomized and then injected with the same dose of each estrogen. This treatmentcompletely suppressed postcastration changes in FSH cells. This also resulted in an exag-geration of estrogen-induced LTII cell hypertrophy. Alterations induced by estradiol-17 jawere similar to but milder than those in the case of the hexestrol difatty acid esters, although hexestrol exerted no morphological effects.