PRELORDOTIC BEHAVIOR IN THE HAMSTER - HORMONALLY MODULATED TRANSITION FROM AGGRESSION TO SEXUAL RECEPTIVITY

Analyzed the behavioral responses of 60 female golden hamsters to sexually experienced males as a function of the stage of the female's estrous cycle. Exogenous estradiol or estradiol followed by progesterone was given to ovariectomized Ss to determine the role of these hormones in regulation of cyclic changes in the female's response to the male. Ss were paired daily with sexually active males for 10 min, and behavioral interactions were recorded. Significantly more fighting occurred during early diestrus than later in the cycle. By 8 hrs prior to the onset of sexual receptivity, 86% of Ss exhibited a behavior resembling the onset of lordosis without immobilization. Following ovariectomy, fighting was at a high level. Estradiol replacement over 28 days resulted in a significant decrease in aggression and increase in display of the prelordotic response. Initially, treatment with progesterone following 7 days of estradiol caused lordosis display. After 24 hrs a significant increase in aggression, which continued as long as progesterone was present, was observed. Thus, estradiol causes the female to become tolerant of the male's approach, the female exhibiting prelordosis in response to the male's investigation. Estradiol and progesterone are necessary for normal sexual receptivity; however, after 24 hrs, estrogen/progesterone-treated females become agonistic to the male. (15 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1979 American Psychological Association.