Department of Biology, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON, N2L 3C5, Canada.
Department of Biology, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON, N2L 3C5, Canada.
Aquat Toxicol. 2019 Dec;217:105327. doi: 10.1016/j.aquatox.2019.105327. Epub 2019 Oct 19.
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.
许多人为来源，如纸浆厂和污水处理厂的污水，含有雄激素内分泌干扰化合物，改变水生生物的生殖状态。目前的研究注入成年雄性褐菖鲉（Fundulus heteroclitus）与 0（对照），1 pg/g，1 ng/g 或 1μg/g 体重的模型雄激素 5α-二氢睾酮（DHT）诱导的血浆性激素抑郁，一个以前的观察到的 DHT 在鱼类中的作用。在性荷尔蒙抑郁和恢复期间评估了一套性腺甾体生成基因。鱼被采样 6，12，16，18，24，30 和 36 小时后注射，并立即或在 18°C 孵育 24 小时以确定体外性腺激素产生，然后冷冻睾丸组织的部分。血浆睾酮（T）和 11-酮睾酮（11KT）抑郁开始于 24 小时后注射。在 36 小时后注射时，血浆 T 仍然抑郁，而血浆 11KT 已经恢复。在速冻组织中，血浆性激素抑郁与关键甾体生成基因的下调之间存在相关性，包括甾体生成急性调节蛋白（STAR），细胞色素 P450 17a1（CYP17A1），3β-羟类固醇脱氢酶（3βHSd），11β-羟类固醇脱氢酶（11βHSd）和 17β-羟类固醇脱氢酶（17βHSd）。与以前的研究类似，3βHSd 是 DHT 暴露期间第一个也是最敏感的基因。体外组织的基因反应更加多变，包括在激素抑制期间 3βHSd，11βHSd 和 STAR 的上调。体外睾丸与速冻组织之间甾体生成基因的差异表达可能是由于缺乏下丘脑-垂体-性腺轴的调节剂存在于整体动物系统中。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，用于性腺甾体生成基因表达，以更准确地反映体内反应。
