51. Estrogen-dependent estrous behavior in rabbits is antagonized by the antiprogestin RU486.
- Author
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González-Mariscal G, Gallegos JA, Rueda Morales RI, and Hoffman K
- Subjects
- Animals, Estradiol analogs & derivatives, Estradiol pharmacology, Estrogen Receptor alpha drug effects, Estrogen Receptor alpha physiology, Female, Injections, Male, Posture, Rabbits, Receptors, Progesterone drug effects, Receptors, Progesterone physiology, Estrogens physiology, Estrus drug effects, Estrus physiology, Hormone Antagonists pharmacology, Mifepristone pharmacology, Sexual Behavior, Animal drug effects, Sexual Behavior, Animal physiology
- Abstract
Estrogen receptor-alpha (ERα) dimerizes with unliganded progesterone receptor (PR) in target tissues to trigger genomic and non-genomic effects. In ovariectomized rats the antiprogestin RU486 or antisense nucleotides against PR antagonize estradiol-induced sexual receptivity. We determined the relevance of unliganded PR for the expression of estrogen-dependent scent-marking (chinning) and sexual receptivity by injecting RU486 to: a) ovariectomized (ovx) rabbits given estradiol benzoate (EB; 5μg/day); b) intact rabbits. Chinning and lordosis were quantified in ovx animals before (5days; baseline) and during hormonal treatments: EB+RU486 (20mg/day; n=18) or EB+vehicle (n=18). On treatment day 4 LQ (lordosis quotient) increased in both groups, relative to baseline (mean±se): LQ=1±5 (baseline) vs 25±21 (EB+RU486) and 2±6 (baseline) vs 37±29 (EB+vehicle). On day 9 LQ values were: 22±23 (EB+RU486) and 54±39 (EB+vehicle). Chinning increased only in the EB+vehicle group (day 9=55±46 vs baseline=17±20 marks/10min). In intact rabbits one RU486 injection: reduced the LQ from 72±7to 36±8 five hrs later, increased the latency to receive first ejaculation from 45 to 98s, and decreased the number of ejaculations received in the test from 3 to 2 but did not modify mounting latency or chinning. Results support a participation of unliganded PR for the induction (ovx) and maintenance (intact) of rabbit estrous behavior by estrogens., (Copyright © 2017 Elsevier Inc. All rights reserved.)
- Published
- 2017
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