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pubmed:otherAbstract |
PIP: Gonadotropin release after synthetic LH-RH injection was studied under a variety of experimental conditions. In male subjects, LH-RH (25 mcg) induces release of LH and FSH before and during puberty, but only of LH in adults. Larger doses of LH-RH do induce FSH release, with LH release proportional to LH-RH dose; FSH release is smaller than LH release and follows it. In prepuberal females, LH-RH induces a large release of FSH and a weak release of LH. In puberty, LH response becomes greater than FSH. In eugonadal women, FSH and LH responses are more marked during luteal phase than during preovulatory phase. Nonsequential hormonal contraceptives inhibit FSH and LH response to 50 mcg of LH-RH, but not to 100 mcg. In postmenopausal women, LH increases after 25 mcg of LH-RH; 200 mcg ethinyl estradiol for 5 days permits an increase of both gonadotropins. These results suggest that gonadotropin response to LH-RH depends on endocrine equilibrium and gonadal steroids which may modify the synthesis and/or release of pituitary gonadotropins. On the basis of selective LH response to small doses of LH-RH, ti is speculated that an FSH releasing factor may exist.
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