Androgen regulation of muscle fiber type in the sexually dimorphic larynx of Xenopus laevis
Androgen regulation of muscle fiber type in the sexually dimorphic larynx of Xenopus laevis
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DOI：
10.1523/jneurosci.07-10-03198.1987
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发表时间：
1987-10
期刊：
影响因子：
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通讯作者：
D. Sassoon;G. Gray;D. Kelley
中科院分区：
文献类型：
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作者：
D. Sassoon;G. Gray;D. Kelley
我们使用组织化学技术[腺嘌呤三磷酸酶（ATP酶）和琥珀酸脱氢酶（SDHase）活性测定]，以确定肌肉纤维类型的非洲爪蟾的喉。雄性肌肉由一种纤维类型组成，中等大小的纤维（约9微米2），对酸稳定的ATP酶染色轻微，对SDHase活性染色强烈。相比之下，雌性有3种纤维类型：ATP酶和SDHase染色强烈的小纤维（约6微米2），中等大小的纤维（约13微米2），ATP酶中度染色，SDHase染色较深，大纤维（约15微米2）几乎没有SDHase或ATP酶活性。长期去势（6个月）对成年雄性纤维的组织化学染色没有影响。长期睾酮治疗（5个月）增加了成年女性中等大小，中度染色纤维的比例，并降低了小，深色染色纤维和大，轻度染色纤维的比例。变态时，雌雄鱼都有3种肌纤维，其ATP酶活性与雌鱼相似。然而，没有观察到SDHase活性。用睾酮处理青少年3周，结果肌纤维几乎完全雄性化，这通过横截面积增加、ATP酶染色均匀和SDHase活性显著增加来判断。因此，青少年肌肉比成年女性肌肉对睾酮的反应更敏感。我们建议，统一的雄性喉肌的代谢特性有助于生产快速（66 Hz）的配偶呼叫发声的特点，这一物种。此外，我们的研究结果表明，雄激素直接喉肌纤维的雄性化在postmetamorphic发展。
We used histochemical techniques [assays for adenine triphosphatase (ATPase) and succinate dehydrogenase (SDHase) activity] to identify muscle fiber types in the larynx of Xenopus laevis. Male muscle is made up of one fiber type, medium-sized fibers (approximately 9 microns2) that stain lightly for acid-stable ATPase and intensely for SDHase activity. In contrast, the female has 3 fiber types: small fibers (approximately 6 microns2) that stain intensely for ATPase and SDHase, medium-sized fibers (approximately 13 microns2) with moderate staining for ATPase and dark staining for SDHase, and large fibers (approximately 15 microns2) with little SDHase or ATPase activity. Long- term castration (6 months) has no effect on histochemical staining of adult male fibers. Long-term testosterone treatment (5 months) increases the proportion of medium-sized, moderately staining fibers in adult females, and reduces the proportion of both the small, darkly staining fibers and the large, lightly staining fibers. At metamorphosis, both males and females have 3 fiber types whose ATPase activity is similar to that of the adult female. However, no SDHase activity is observed. Treatment of juveniles for 3 weeks with testosterone results in nearly complete masculinization of muscle fibers, as judged by increased cross-sectional area, homogeneous ATPase staining, and a marked increase in SDHase activity. Thus, juvenile muscle is considerably more responsive to testosterone than is adult female muscle. We propose that the uniform metabolic properties of male laryngeal muscle contribute to the production of the rapid (66 Hz) mate call vocalizations characteristic of this species. Further, our results suggest that androgens direct the masculinization of laryngeal muscle fibers during postmetamorphic development.