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Sex differences in response to discrete estradiol injections
Hormones and Behavior
|December 1, 1986
Summary
Perinatal androgen exposure makes male rats insensitive to female sexual behaviors. Discontinuous estradiol (E2) and progesterone (P) hormone treatments did not reverse this insensitivity in Sprague-Dawley rats.
Area of Science:
- Neuroendocrinology
- Behavioral Endocrinology
- Reproductive Biology
Background:
- Perinatal androgen exposure typically results in adult male rats being insensitive to hormones that activate female sexual behavior.
- Recent studies suggested fluctuating estradiol (E2) levels might reverse this insensitivity in Wistar rats.
- This study investigated if similar hormonal regimens could reverse insensitivity in Sprague-Dawley rats.
Purpose of the Study:
- To determine if a specific hormonal regimen of discontinuous estradiol (E2) and progesterone (P) could reverse the developmental insensitivity to female sexual behavior activation in adult male Sprague-Dawley rats.
- To compare the effects of this regimen in Sprague-Dawley males versus females.
- To test the hypothesis that discontinuous E2 stimulation can overcome developmental determinants of sex differences in hormone responsiveness.
Main Methods:
- Adult gonadectomized Sprague-Dawley rats received repeated cycles of two spaced E2 injections followed by progesterone (P) or oil.
- Mating behavior tests were conducted after hormone administration.
- Receptivity, lordosis quotients, and proceptivity were measured and compared between sexes.
Main Results:
- The discontinuous E2 and P hormonal regimen did not reverse the insensitivity to female sexual behavior in male Sprague-Dawley rats.
- Receptivity scores, lordosis quotients, and proceptivity remained negligible in males, unlike in females.
- Progesterone facilitation of sexual receptivity following E2 was observed in females but not in males.
Conclusions:
- The findings do not support the hypothesis that discontinuous E2 stimulation reverses developmental determinants of sex differences in hormone-mediated female sexual behaviors.
- Developmental effects of perinatal androgens appear to maintain male refractoriness to E2 and P activation of female sexual behavior in Sprague-Dawley rats.
- This hormonal treatment pattern is ineffective in overcoming established sex differences in behavioral responsiveness to sex steroids.
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