Blockade of progesterone-activated estrous behavior in rats by intracerebral anisomycin is site specific.
The hypothesis that progesterone (P) activates estrous behavior in estrogen-primed female rats via a protein synthetic mechanism was examined. The protein synthesis inhibitor anisomycin was applied intracerebrally via 28-gauge bilateral implants to neural sites implicated in the mediation of estrous responsiveness. Results showed that anisomycin blockade of P-activated estrous behavior was neural site specific. Animals with anisomycin placed in the ventromedial hypothalamus (VMH) (n = 27) showed low levels of lordosis and solicitation behavior 4 h after the subcutaneous administration of 500 micrograms P, whereas animals with anisomycin implants in the preoptic area (n = 11) or the midbrain area in the region of the interpeduncular nucleus (n = 11) displayed high levels of estrous behavior. No deficits in open-field activity were observed following localized anisomycin treatment, and all animals appeared to be healthy. Results of the present study are consistent with the hypothesis that P acts to promote estrous behavior via a receptor-mediated genomic protein synthetic mechanism, and provide additional evidence that the VMH is the primary site of P action.
D000818:Animals; D000841:Anisomycin / Q000494:pharmacology*; D002369:Castration; D004958:Estradiol / Q000494:pharmacology; D004971:Estrus / Q000187:drug effects*; D005260:Female; D009043:Motor Activity / Q000187:drug effects; D011247:Pregnancy; D011301:Preoptic Area / Q000187:drug effects; D011374:Progesterone / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology*; D051381:Rats; D011980:Receptors, Progesterone / Q000187:drug effects; D012726:Sexual Behavior, Animal / Q000187:drug effects*; D013681:Tegmentum Mesencephali / Q000187:drug effects; D014697:Ventromedial Hypothalamic Nucleus / Q000187:drug effects*
D011759:Pyrrolidines; D011980:Receptors, Progesterone; D011374:Progesterone; D004958:Estradiol; D000841:Anisomycin