Numerous anthropogenic sources, such as pulp mill and sewage treatment effluents, contain androgenic endocrine disrupting compounds that alter the reproductive status of aquatic organisms. The current study injected adult male mummichog (Fundulus heteroclitus) with 0 (control), 1 pg/g, 1 ng/g or 1 μg/g body weight of the model androgen 5α-dihydrotestosterone (DHT) with the intent to induce a period of plasma sex hormone depression, a previously-observed effect of DHT in fish. A suite of gonadal steroidogenic genes were assessed during sex hormone depression and recovery. Fish were sampled 6, 12, 16, 18, 24, 30 and 36 h post-injection, and sections of testis tissue were either snap frozen immediately or incubated for 24 h at 18 °C to determine in vitro gonadal hormone production and then frozen. Plasma testosterone (T) and 11-ketotestosterone (11KT) were depressed beginning 24 h post-injection. At 36 h post-injection plasma T remained depressed while plasma 11KT had recovered. In snap frozen tissue there was a correlation between plasma sex hormone depression and downregulation of key steroidogenic genes including steroidogenic acute regulatory protein (star), cytochrome P450 17a1 (cyp17a1), 3β-hydroxysteroid dehydrogenase (3βhsd), 11β-hydroxysteroid dehydrogenase (11βhsd) and 17β-hydroxysteroid dehydrogenase (17βhsd). Similar to previous studies, 3βhsd was the first and most responsive gene during DHT exposure. Gene responses from in vitro tissue were more variable and included the upregulation of 3βhsd, 11βhsd and star during the period of hormone depression. The differential expression of steroidogenic genes from the in vitro testes compared to the snap frozen tissues may be due to the lack of regulators from the hypothalamo-pituitary-gonadal axis present in whole-animal systems. Due to these findings it is recommended to use snap frozen tissue, not post-incubation tissue from in vitro analysis, for gonadal steroidogenic gene expression to more accurately reflect in vivo responses.

中文翻译：

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5α-二氢睾丸激素对雄性木乃伊（Fundulus heteroclitus）的生理作用是剂量和时间依赖性的。

许多人为来源，例如制浆厂和污水处理废水，都含有破坏雄性内分泌的化合物，这些化合物会改变水生生物的繁殖状况。当前研究为成年雄性木乃伊（Fundulus heteroclitus）注射了0（对照），1 pg / g，1 ng / g或1μg/ g体重的雄激素5α-二氢睾丸激素（DHT）模型，目的是诱导一段时间血浆性激素降低的现象，这是以前在鱼类中观察到的DHT效应。在性激素抑制和恢复期间评估了一套性腺类固醇生成基因。在注射后6、12、16、18、24、30和36小时对鱼取样，将睾丸组织切片立即速冻或在18℃下温育24小时以确定体外性腺激素的产生，然后冷冻。注射后24小时开始，血浆睾丸激素（T）和11-酮睾酮（11KT）受到抑制。在注射后36小时，血浆T保持压低，而血浆11KT已恢复。在快速冷冻的组织中，血浆性激素抑制与关键类固醇生成基因的下调之间存在相关性，这些基因包括类固醇生成的急性调节蛋白（星型），细胞色素P450 17a1（cyp17a1），3β-羟基类固醇脱氢酶（3βhsd），11β-羟基类固醇脱氢酶（11βhsd）和17β-羟基类固醇脱氢酶（17βhsd）。与以前的研究类似，DHT暴露过程中3βhsd是第一个也是反应最强的基因。体外组织的基因反应更具可变性，包括在激素抑制期间3βhsd，11βhsd和星形蛋白的上调。与速冻组织相比，来自体外睾丸的类固醇生成基因的差异表达可能是由于在整个动物系统中缺乏来自下丘脑-垂体-性腺轴的调节剂。由于这些发现，建议使用速冻组织而不是体外分析的孵育后组织进行性腺类固醇生成基因表达，以更准确地反映体内反应。