Wu Guan-Chung, Li Hau-Wen, Luo Jia-Wun, Chen Chi, Chang Ching-Fong
Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan
Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan.
Biol Reprod. 2015 Jun;92(6):158. doi: 10.1095/biolreprod.114.126953. Epub 2015 Apr 8.
In most vertebrates, hermaphroditism results in infertility. However, hermaphroditism occurs in 6% of teleosts, which primarily undergo protogyny. Here, to elucidate the transient stage from gonochorism to hermaphroditism, juvenile black porgies as a model animal were fed a diet containing estradiol (E2) for 3 mo, followed by withdrawal of E2 treatment. The E2-terminated fish had ectopically located oocytes in the regenerated testes. Antimüllerian hormone (amh) was strongly expressed in the Sertoli cells with type A spermatogonia and follicle cells with vitellogenic oocytes. Amh was robustly expressed in the ectopic oocytes-bordering region of regenerated testes and in testes with nonsynchronous spermatogenesis. This Amh was released by Sertoli cells and aggregated in the area containing type A spermatogonia in the ectopic oocytes-bordering region. Our in vitro results show that exogenous recombinant Amh (rAmh) can inhibit type A spermatogonia proliferation in the testis but not oogonia proliferation in the ovary. We suggest that Amh-arrested spermatogonia A may act as a boundary to block intercellular communication (i.e., prevent peptide factors released from female tissue to alter the sexual fate of type A spermatogonia) and further inhibit female growth. These results suggest that black porgy can prevent ectopic female growth in the testis and maintain male function of the digonic gonad (testes and ovary separated by the connective tissue) through Amh action. This function of amh might shed light on why the majority of syngonic fish undergo protogyny (female-to-male sex change).
在大多数脊椎动物中，雌雄同体导致不育。然而，6%的硬骨鱼会出现雌雄同体现象，它们主要经历雌性先熟。在此，为了阐明从雌雄异体到雌雄同体的过渡阶段，以幼年黑鲷作为模式动物，给它们喂食含雌二醇（E2）的饲料3个月，随后停止E2处理。停止E2处理后的鱼在再生睾丸中出现异位的卵母细胞。抗缪勒氏管激素（amh）在具有A型精原细胞的支持细胞和具有卵黄生成卵母细胞的卵泡细胞中强烈表达。Amh在再生睾丸的异位卵母细胞边界区域以及精子发生不同步的睾丸中大量表达。这种Amh由支持细胞释放，并聚集在异位卵母细胞边界区域含有A型精原细胞的区域。我们的体外实验结果表明，外源性重组Amh（rAmh）可以抑制睾丸中A型精原细胞的增殖，但不能抑制卵巢中卵原细胞的增殖。我们认为，被Amh阻滞的A型精原细胞可能作为一个边界来阻断细胞间通讯（即阻止从雌性组织释放的肽因子改变A型精原细胞的性命运），并进一步抑制雌性生长。这些结果表明，黑鲷可以通过Amh的作用防止睾丸中异位的雌性生长，并维持两性性腺（由结缔组织分隔的睾丸和卵巢）的雄性功能。Amh的这种功能可能有助于解释为什么大多数两性融合的鱼类会经历雌性先熟（从雌性到雄性的性转变）。
