Neonatal androgen influences sexual motivation but not the masculine copulatory motor pattern in the rat.
Masculine sexual responses displayed by female rats, were compared to those of males. Twenty-five percent of females mounted and 19% showed intromission behavior, but none of them displayed the ejaculation pattern. Masculine sexual behavior was displayed in all stages of the estrous cycle. Accelerometric and spectrum frequency analysis of electrical signals generated by pelvic movements during mounting and intromission showed that these patterns were identical in both sexes excepting that mount duration in females was longer than in males. Neonatal androgenization of females increased the display of intromission patterns. Treatment of ovariectomized rats, androgenized or not, with either estradiol benzoate or testosterone propionate stimulated masculine sexual behavior. The ejaculatory pattern was only displayed by neonatally androgenized females. Mounting and intromission motor patterns of females under steroid treatment, and ejaculations of neonatally androgenized females, were similar to those of males. The results show that the organization of the movements involved in masculine sexual behavior in rats are identical in both sexes, thus suggesting that the neural circuits controlling these behaviors could be identical. Neonatal or postpubertal androgen in the rat influences the frequency with which male-like responses are displayed, but not their temporal (frequency, rhythm) or dynamic (acceleration, vigour) characteristics.
D000818:Animals; D000831:Animals, Newborn; D002369:Castration; D003307:Copulation / Q000502:physiology*; D004542:Ejaculation / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology; D008297:Male; D009042:Motivation / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D012733:Sex Differentiation / Q000187:drug effects*; D012726:Sexual Behavior, Animal / Q000187:drug effects*; D013739:Testosterone / Q000494:pharmacology*
D013739:Testosterone; D004958:Estradiol