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The Effect of an Antiprogestin Compound (RU486) on Gonadotropin and Prolactin Release in vivo
Author(s) -
Arakawa Satoko,
Ohkawa Tomi,
Kambegawa Akira,
Okinaga Shoichi,
Arai Kiyoshi
Publication year - 1988
Publication title -
asia‐oceania journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 50
eISSN - 1447-0756
pISSN - 0389-2328
DOI - 10.1111/j.1447-0756.1988.tb00141.x
Subject(s) - prolactin , medicine , endocrinology , estrous cycle , gonadotropin , radioimmunoassay , estradiol benzoate , mifepristone , in vivo , chemistry , luteinizing hormone , hormone , biology , pregnancy , ovariectomized rat , genetics , microbiology and biotechnology
We administered oil (group A), 5 mg of progesterone (P 4 ) (group B), or 5 mg of P 4 +5mg of RU486 (antiprogestin) (group C) to castrated female rats treated with estradiol benzoate (EB). Serum LH, FSH, and prolactin (PRL) levels 24 hr after the injections were measured by specific radioimmunoassay (RIA) methods. Serum LH levels of group B were significantly lower than those of groups A and C, but serum levels of FHS and PRL showed different patterns. We administered oil (group D) or 5 mg of RU486 (group E) to normal cycling female rats. The serum levels of LH, FSH, and PRL of group E were higher than those of group D. These results confirmed that P 4 had an inhibitory effect on LH release in spayed rats pretreated with EB and in normal rats with estrous cycles. The FSH and PRL levels are reportedly depressed by an intrinsic surge of P 4 in normal rats during estrous cycles. And this inhibitory effect of P 4 on the hypothalamo‐pituitary system was canceled by RU486. No significant difference was observed in pituitary weight or pituitary content of LH and FSH in this series of experiments.