Abstract：
Prior studies demonstrated that gonadal differentiation in the rice field frog, Hoplobatrachus rugulosus, was of an undifferentiated type since all individuals had ovaries at complete metamorphosis. However, the steroidogenic potential of the gonad is still unknown. In this study, H. rugulosus were obtained by stimulating fertilization in the laboratory under natural light and temperature conditions. The gonads were collected and their steroidogenic potential was evaluated by determining the expression level of messenger RNA (mRNA) encoding for cytochrome P450 17-hydroxylase/C17-20 lyase (CYP17) and cytochrome P450 aromatase (CYP19) using quantitative real-time RT-PCR and the localization of CYP17 mRNA in tissues by in situ hybridization. The CYP17 mRNA levels in males at 4-11 weeks postmetamorphosis were higher than in female and intersex gonads. This corresponded to their localization in the gonadal tissues, where CYP17 signals were specifically detected in the Leydig cells of the testis at 5-16 weeks postmetamorphosis but was undetectable in all ovary samples. The CYP19 mRNA levels in females at 4-11 weeks postmetamorphosis was higher than in male and intersex gonads, which corresponded with gonadal development, indicating the potential steroidogenic function of the ovary. Based on the present results, the role of CYP17 and CYP19 mRNA in sex differentiation in H. rugulosus may occur after gonadal sex differentiation and the steroidogenic potential of the gonads exhibited a sexual dimorphic pattern. These results provide a crucial basis for further research on the developmental biology in anuran species.
摘要：
先前的研究表明，稻田蛙的性腺分化，Hoplobatrachusrugulous，是未分化类型，因为所有个体的卵巢都处于完全变态状态。然而,性腺的类固醇生成潜力仍然未知。在这项研究中,H.rugulosus是在实验室中在自然光和温度条件下通过刺激施肥获得的。收集性腺并通过使用定量实时RT-PCR和通过原位杂交确定编码细胞色素P45017-羟化酶/C17-20裂解酶(CYP17)和细胞色素P450芳香化酶(CYP19)的信使RNA(mRNA)的表达水平来评估其类固醇生成潜力。变态后4-11周，男性的CYP17mRNA水平高于女性和双性性腺。这对应于它们在性腺组织中的定位，其中在变态后5-16周的睾丸间质细胞中特异性检测到CYP17信号，但在所有卵巢样品中均未检测到。变态后4-11周女性的CYP19mRNA水平高于男性和双性性腺，与性腺发育相对应，表明卵巢潜在的类固醇生成功能。根据目前的结果，CYP17和CYP19mRNA在H.rugulosus性别分化中的作用可能发生在性腺性别分化后，性腺的类固醇生成潜力表现出性二态模式。这些结果为进一步研究无性系物种的发育生物学提供了重要基础。
