Hormone-sensitive stages in the sexual differentiation of laryngeal muscle fiber number in Xenopus laevis.
Hormone-sensitive stages in the sexual differentiation of laryngeal muscle fiber number in Xenopus laevis.
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发表时间：
1990-11
期刊：
影响因子：
4.6
通讯作者：
Melanie L. Marin;Martha L. Tobias;Darcy B. Kelley
中科院分区：
文献类型：
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作者：
Melanie L. Marin;Martha L. Tobias;Darcy B. Kelley
成年雄性非洲爪蟾（Xenopus laevis）发声器官中的肌纤维数量超过了成年雌性非洲爪蟾。这种性别差异是由于快速纤维除了在男性之间的变态结束，后变态阶段0（PM 0）和PM 2。在PM0时，雄性和雌性青蛙的喉肌纤维数量相似。然后，男性比女性增加更多的肌肉纤维，达到成年值是女性数量的1.7倍。在PM0时去势的雄性动物具有与雌性动物相同的纤维数量。在PM0时切除卵巢不会改变女性的肌纤维添加。在PM2的性腺切除术对两种性别的纤维添加没有影响。如果雌性在变态时卵巢被睾丸取代，则其肌肉纤维数量达到雄性。外源性睾酮治疗在PM0显着增加纤维数量的女性，但不是在男性。在PM2给予外源性睾酮对女性的纤维数量没有影响，但会降低男性的纤维数量。我们的结论是，睾丸是必要的喉肌纤维的显着增加看到在男性X。在PM0和PM2之间。在具有睾丸的雌性动物中，可以诱导出肌肉纤维增加的阳性模式。睾丸分泌雄激素可能是喉肌纤维数目雄性化的原因。在PM2之后，雄激素不再是肌肉纤维添加所必需的，并且不能增加女性的纤维数量。
The number of muscle fibers in the vocal organ of the adult male African clawed frog, Xenopus laevis, exceeds that of adult females. This sex difference is the result of rapid fiber addition in males between the end of metamorphosis, post-metamorphic stage 0 (PM0) and PM2. At PM0, male and female frogs have similar numbers of laryngeal muscle fibers. Males then add more muscle fibers than females and achieve an adult value that is 1.7 times the female number. Males castrated at PM0 have the same fiber number as females. Ovariectomy at PM0 does not alter muscle fiber addition in females. Gonadectomy at PM2 has no effect on fiber addition in either sex. Females attain masculine muscle fiber number if their ovaries are replaced with a testis at metamorphosis. Exogenous testosterone treatment at PM0 significantly increases fiber number in females but not in males. Exogenous testosterone given at PM2 has no effect on fiber number in females but decreases fiber number in males. We conclude that the testes are necessary for the marked addition of laryngeal muscle fibers seen in male X. laevis between PM0 and PM2. The masculine pattern of muscle fiber addition can be induced in females provided with a testis. Androgen secretion from the testes most probably accounts for masculinization of laryngeal muscle fiber number. After PM2, androgens are no longer necessary for muscle fiber addition and cannot increase fiber number in females.