PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “GONADOTROPINS, PITUITARY”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1999

Steroid feedback on gonadotropin release and pituitary gonadotropin subunit mRNA in mice lacking a functional estrogen receptor alpha.

Steroid hormones regulate levels of gonadotropin mRNA in the pituitary, and gonadotropic hormones in plasma. To determine whether estrogen receptor alpha (ERalpha) mediates steroid negative feedback, wild type (WT) and estrogen receptor alpha knockout (ERalphaKO) mice of both sexes were gonadectomized and implanted with a Silastic capsule containing either estradiol (E2), dihydrotestosterone (DHT), testosterone, or a blank capsule. Ten days later, plasma luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels were measured. Pituitary mRNA levels of gonadotropin subunit (alpha, LHbeta, FSHbeta) and prolactin (PRL) were quantified. LH levels in gonad-intact ERalphaKO females were elevated, similar to values seen following gonadectomy. By contrast, serum LH concentrations in gonad-intact ERalphaKO males were low and rose following gonadectomy, suggesting androgen feedback. Estradiol treatment significantly decreased plasma LH in WT animals, but not in ERalphaKOs. In fact, in female ERalphaKOs, our dose of E2 increased plasma levels of LH as compared with untreated, ovariectomized ERalphaKOs. All the steroid treatments suppressed LH in WT animals whereas only DHT consistently suppressed LH concentrations in ERalphaKO mice. The postgonadectomy rise in plasma FSH was prevented by steroid treatments in WT females, but not in any of the other groups. Gonadotropin subunit and PRL mRNA responses to E2 treatment (both inhibitory and stimulatory) were absent in ERalphaKO mice, suggesting a critical role for ERalpha. Although E2 can exert negative feedback effects on LH release in both males and females by actions at the ERalpha, the androgen receptor plays the primary physiological role in the male mouse.

Animals↗
PubMed1981

Effects of preceding androgen therapy on testicular response to human pituitary gonadotropin in hypogonadotropic hypogonadism: a study of three patients.

There is some uncertainty about the choice of initial therapy to induce virilization in men with hypogonadotropic hypogonadism (HH) who may subsequently desire fertility. Three patients with HH and azoospermia are described. All had received long-term androgen therapy in fully virilizing doses, and two also received interval androgen therapy. Spermatogenesis occurred in all three patients after treatment with human chorionic gonadotropin and human pituitary gonadotropin, and the wives of all three conceived. For two patients conception occurred three times in response to gonadotropin therapy, and libido and potency were maintained with testosterone between each conception. It is concluded that preceding long-term therapeutic doses of androgen do not impair subsequent induction of spermatogenesis in patients with HH.

Adult↗