Lordosis: Inhibiting effects of progesterone in the female rat

• Published in: Hormones and behavior Vol. 8; no. 3; pp. 391 - 402
• Main Authors: Marrone, Babetta L., Rodriguez-Sierra, Jorge F., Feder, Harvey H.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.06.1977
• Subjects: Animals; Benzoates; Castration; Depression, Chemical; Dose-Response Relationship, Drug; Estradiol - pharmacology; Estradiol Congeners - pharmacology; Female; Progesterone - pharmacology; Progesterone Congeners - pharmacology; Rats; Sexual Behavior, Animal - drug effects; Estrogens; Contraceptive Agents, Estrogen > administraction and dosage; Biology; Hormones; Urogenital Surgery; Research Methodology; Progesterone > administraction and dosage; Contraceptive Agents > side effects; Contraceptive Agents, Female > administraction and dosage; Clinical Research; Female Sterilization; Surgery; Physiology; Behavior; Animals, Laboratory; Progestational Hormones; Ovariectomy; Contraceptive Agents > administraction and dosage; Estradiol Benzoate > administraction and dosage; Contraception; Contraceptive Agents, Estrogen > side effects; Family Planning; Gynecologic Surgery; Endocrine System; Progesterone > side effects; Treatment; Estradiol Benzoate > side effects; Sex Behavior; Contraceptive Agents, Female > side effects
• ISSN: 0018-506X; 1095-6867
• DOI: 10.1016/0018-506X(77)90013-7

Progesterone has two types of inhibitory effects on female sexual behavior that have been well-documented in the guinea pig. The first occurs when high levels of progesterone are present around the start of the estrogen-priming process (“concurrent inhibition”). The second occurs immediately after the display of an estrogen-progesterone-induced period of estrous behavior (“sequential inhibition”). In the present set of experiments, we show that the rat, like the guinea pig, is capable of exhibiting both of these inhibitory effects of progesterone. However, rats require higher doses of progesterone than guinea pigs, at least for concurrent inhibition to be evident. In addition, we show that the dose of progesterone required in a single injection to produce concurrent inhibition is higher than the dose required to produce sequential inhibition in rats. A theory of how progesterone may be accomplishing its inhibitory effects on female sexual behavior in rodents is presented.