Thyroid hormone controls the onset of androgen sensitivity in the developing larynx of Xenopus laevis.
Thyroid hormone controls the onset of androgen sensitivity in the developing larynx of Xenopus laevis.
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甲状腺激素控制非洲爪蟾发育中喉部雄激素敏感性的发生。
DOI：
10.1006/dbio.1996.9990
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Kelley,DB
中科院分区：
文献类型：
--
作者：
Robertson,JC;Kelley,DB
性腺分化、雄激素刺激的喉部生长的开始以及喉部神经支配中性别差异的发生，在时间上都与甲状腺激素（TH）诱导的非洲爪蟾的变态相一致。为了探索TH在非洲爪蟾雄激素敏感的发声神经肌肉系统个体发育中的作用，我们检查了通过用以下药物治疗来阻断变态的蝌蚪的性腺和喉部发育。甲状腺素合成抑制剂丙硫氧嘧啶（PTU）。 PTU 治疗并未阻止性腺分化。经过 PTU 处理的雄性蝌蚪的睾丸具有生精小管和晚期雄性生殖细胞，而雌性蝌蚪则存在 1 期卵母细胞。与性腺相反，PTU 确实阻碍了喉部的形态发育。用 PTU 处理 50 或 100 天的蝌蚪的喉结构与第 54 阶段对照蝌蚪的喉结构相似。 PTU 处理的动物没有表现出未处理动物中所见的喉软骨的广泛发育。甲状腺功能减退蝌蚪的喉软骨表现出低密度和最小的软骨细胞图案；未治疗 50 天和 100 天的动物没有出现复杂的管腔和扩张肌的显着扩张特征。 PTU 治疗完全阻止了因暴露于外源性雄激素（二氢睾酮）而引起的喉部生长。甲状腺功能减退蝌蚪没有表现出年龄匹配对照的喉神经轴突数量特征的下降，喉神经轴突数量也没有性别二态性。 PTU 治疗还干扰喉轴突的髓鞘形成。我们的结论是，虽然性腺分化与 TH 无关，但雄激素敏感的喉发育和性二形性喉神经支配需要暴露于分泌的 TH。
Gonadal differentiation, the onset of androgen-stimulated laryngeal growth and the genesis of a sex difference in laryngeal innervation, all temporally coincide with thyroid hormone (TH)-induced metamorphosis inXenopus laevis.To explore the role TH plays in the ontogeny of theXenopusandrogen-sensitive vocal neuromuscular system, we examined gonadal and laryngeal development in tadpoles in which metamorphosis had been blocked by treatment with the thyroxine synthesis inhibitor propylthiouracil (PTU). PTU treatment did not arrest gonadal differentiation. Testes from PTU-treated male tadpoles had seminiferous tubules and advanced stage male germ cells, while in females stage 1 oocytes were present. In contrast to the gonads, PTU did block morphological development of the larynx. Tadpoles treated with PTU for 50 or 100 days had larynges which structurally resembled those of stage 54 control tadpoles. PTU-treated animals did not exhibit the extensive development of the laryngeal cartilage seen in untreated animals. Laryngeal cartilages of hypothyroid tadpoles exhibited low density and minimal patterning of chondrocytes; the complex lumen and marked expansion of the dilator muscles characteristic of 50- and 100-day untreated animals were absent. Laryngeal growth evoked by exposure to exogenous androgen (dihydrotestosterone) was entirely prevented by PTU treatment. Hypothyroid tadpoles did not exhibit the decline in laryngeal nerve axon number characteristic of age-matched controls, nor were laryngeal nerve axon numbers sexually dimorphic. PTU treatment also interfered with the myelination of laryngeal axons. We conclude that while gonadal differentiation is independent of TH, androgen sensitive laryngeal development and sexually dimorphic laryngeal innervation require exposure to secreted TH.