Onset of the receptive and proceptive components of feminine sexual behavior in rats following the intravenous administration of progesterone.
The present study was carried out in order to assess the time course of action of progesterone (P) in the facilitation of complete feminine sexual behavior. Female rats (estrogen primed via 5% E2 Silastic capsules) were given 200 micrograms of P either intravenously (iv) or subcutaneously (sc), and tested for estrous behavior at 1/4, 1/2, 1, 2, and 4 hr after treatment. Among iv-treated animals, significant amounts of lordosis behavior were seen as early as 1/2 hr, and a dramatic rise in solicitation behavior was observed at 2 hr. Although sc-treated animals displayed significant amounts of lordosis and solicitation behavior at 2 hr, the behavior was not maximal until 4 hr. Intravenous administration of 400 micrograms P was equipotent to 200 micrograms P, whereas 50 micrograms of iv P was relatively ineffective. A dual mechanism hypothesis pertaining to progesterone's actions in the facilitation of both the receptive and proceptive components of feminine sexual behavior in rats is discussed.
D000818:Animals; D005260:Female; D007275:Injections, Intravenous; D007279:Injections, Subcutaneous; D011187:Posture; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D012726:Sexual Behavior, Animal / Q000187:drug effects*; D013268:Stimulation, Chemical; D013997:Time Factors
D011374:Progesterone