Effects of oestradiol and progesterone on the induction and duration of sexual receptivity in cyclic female rats
Södersten, P.; Hansen, S.
Journal of Endocrinology 74(3): 477-485
1977
ISSN/ISBN: 0022-0795 PMID: 562915 DOI: 10.1677/joe.0.0740477Document Number: 434984
Intact 4-day cyclic rats showed sexual receptivity 24 h after an injection of estradiol benzoate (OB) on any day of the cycle except on the 2nd day after the display of spontaneous estrus. Ovariectomy at the time of OB treatment abolished the behavioral response, but receptivity was restored by progesterone. Progesterone treatment early on the day of behavioral estrus advanced the display of receptivity but did not affect the time at which estrus ended. Repeated treatment of sexually receptive rats with progesterone did not affect the duration of estrus. Sexual receptivity in the intact rat cannot occur in the absence of estradiol and progesterone. Progesterone may not be associated with the mechanisms terminating behavioral estrus in rats. Treatment with OB on the day of estrus can prolong the duration of receptivity but only at a higher dosage than that needed for induction of receptivity.