College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, Shaanxi, China.
Aquat Toxicol. 2012 Oct 15;122-123:19-27. doi: 10.1016/j.aquatox.2012.05.010. Epub 2012 Jun 2.
Previous studies showed that the endocrine disrupting chemicals (EDCs) affect reproductive physiology in teleosts. How the EDCs regulate gonadal steroidogenesis remains to be determined. The gonadal transcript changes of steroidogenic enzyme genes in adult rare minnow Gobiocypris rarus exposed to 17α-ethinylestradiol (EE2) and bisphenol A (BPA) were detected in the present study. The full-length cDNAs encoding steroidogenic enzymes, including steroidogenic acute regulatory protein (StAR), cytochrome P450-mediated side-chain cleavage enzyme (CYP11A1), 3β-hydroxysteroid dehydrogenase (3β-HSD), and cytochrome P450 17 A1 (CYP17A1) were isolated and characterized by RT-PCR and RACE methods. The homology and phylogenetic analyses of the amino acid sequences confirmed that the nucleotide sequences of these steroidogenic genes were correct. The mRNA tissue distribution results indicated that StAR, cyp11a1, and cyp17a1 mRNAs were mainly expressed in the gonads and 3β-HSD was mainly expressed in both the gonads and the brains. The 233 dpf adult G. rarus were exposed to EE2 (25ng/L) and BPA (5, 15, and 50 μg/L) dissolved in dimethyl sulfoxide (DMSO) or control for 7 days. The gonadal mRNA levels of StAR, cyp11a1, 3β-HSD, cyp17a1 and ovarian cytochrome P450 aromatase (cyp19a1a) were quantified by qRT-PCR. Our data indicated that 25 ng/L EE2 had different degrees of inhibitory effects on the expression of steroidogenic genes in the gonads. BPA at different levels caused concentration-specific effects on the mRNA expression of the steroidogenic genes. The transcripts of several ovarian steroidogenic genes were more sensitive to 15 μg/L BPA than that at other two levels. These findings suggest that EE2 could impair gonadal steroidogenesis by suppressing mRNA expression of steroidogenic genes and BPA could cause variations in gonadal steroidogenesis modulation with a potential consequence of compensation for the disturbance.
先前的研究表明，内分泌干扰化学物质（EDCs）会影响鱼类的生殖生理学。EDCs 如何调节性腺甾体生成仍有待确定。本研究检测了 17α-乙炔雌二醇（EE2）和双酚 A（BPA）暴露于稀有鲫（Gobiocypris rarus）成鱼性腺中甾体生成酶基因的转录变化。通过 RT-PCR 和 RACE 方法分离和鉴定了编码甾体生成酶的全长 cDNA，包括甾体生成急性调节蛋白（StAR）、细胞色素 P450 介导的侧链裂解酶（CYP11A1）、3β-羟甾脱氢酶（3β-HSD）和细胞色素 P450 17A1（CYP17A1）。氨基酸序列的同源性和系统发育分析证实了这些甾体生成基因的核苷酸序列是正确的。mRNA 组织分布结果表明，StAR、cyp11a1 和 cyp17a1 mRNA 主要在性腺中表达，3β-HSD 主要在性腺和脑中表达。233 日龄的 G. rarus 成鱼暴露于 EE2（25ng/L）和 BPA（5、15 和 50μg/L）中，溶于二甲基亚砜（DMSO）或对照中 7 天。用 qRT-PCR 定量检测 StAR、cyp11a1、3β-HSD、cyp17a1 和卵巢细胞色素 P450 芳构酶（cyp19a1a）在性腺中的 mRNA 水平。我们的数据表明，25ng/L EE2 对性腺甾体生成基因的表达有不同程度的抑制作用。不同水平的 BPA 对甾体生成基因的 mRNA 表达产生浓度特异性影响。几种卵巢甾体生成基因的转录对 15μg/L BPA 比其他两个水平更敏感。这些发现表明，EE2 可能通过抑制甾体生成基因的 mRNA 表达来损害性腺甾体生成，BPA 可能导致性腺甾体生成调节的变化，从而潜在地补偿干扰。
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