Long-term (39--51 hr) exposure to estradiol in silastic capsules and lordosis behavior of guinea pigs.
Three dosage levels of estradiol (E2) in Silastic capsules were administered to ovariectomized guinea pigs for periods of 39 or 51 hr. At 39 hr., a systemic injection of progesterone was given, and hourly testing began. Dose-dependency of various aspects of lordosis behavior was established at both time intervals, and the serum E2 levels produced by the medium and high dosage levels bracketed those found at the proestrus peak in intact guinea pigs. Although there were no significant behavioral differences between the 39- and 51-hr groups at the individual dosage levels, when the data from all three dosage groups were collapsed, exposure for 51 rather than 39 hr was seen to produce increases in maximum lordosis and heat-duration measures. The results suggest that subtle facilitative effects of estrogen occur very late in the estrogen-conditioning process (even after progesterone is administered).
D000818:Animals; D002214:Capsules; D002369:Castration; D003692:Delayed-Action Preparations; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000008:administration & dosage*; D005260:Female; D006168:Guinea Pigs; D011187:Posture; D012726:Sexual Behavior, Animal / Q000187:drug effects*; D012826:Silicone Elastomers; D013268:Stimulation, Chemical
D002214:Capsules; D003692:Delayed-Action Preparations; D012826:Silicone Elastomers; D004958:Estradiol