The desensitization effect of progesterone on female rat sexual behavior is not due to interference with estrogen priming.
In order to determine if progesterone interferes with estradiol's priming action on progesterone-facilitated sexual behavior, we tested the responsiveness of progesterone-desensitized female rats to the serotonin receptor antagonist, methysergide, and the neuropeptide, luteinizing hormone-releasing hormone. Threshold doses of both compounds were established. Progesterone treatment, which caused a decrease in the lordosis rating in response to a moderate dose of progesterone did not inhibit responsiveness to threshold doses of methysergide or luteinizing hormone-releasing hormone. The results of this study support the notion that progesterone does not interfere with estradiol's priming action on progesterone-facilitated sexual receptivity. Furthermore, they suggest that progesterone's desensitization effect is specific to progesterone-facilitated lordosis.
D000818:Animals; D002369:Castration; D004347:Drug Interactions; D004965:Estrogen Antagonists / Q000494:pharmacology; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D008784:Methysergide / Q000494:pharmacology; D011187:Posture; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012726:Sexual Behavior, Animal / Q000187:drug effects*; D013618:Tachyphylaxis
D004965:Estrogen Antagonists; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D008784:Methysergide