As a frequently detected organophosphate ester in various environmental media, the toxic effects of 2-ethylhexyl diphenyl phosphate (EHDPHP) on aquatic organisms of different sexes remain unclear. In this study, adult zebrafish were exposed to 2.5, 50, 250 µg/L of EHDPHP for 21 days to investigate its sex-dependent reproductive toxicity and related mechanisms. EHDPHP exposure significantly inhibited the reproduction of zebrafish, evidenced by the reduced spawning of females, depressed growth and development of their offspring. EHDPHP induced greater impacts on the changes of sex hormones and vitellogenin (VTG) in the males than females. For females, the synthesis of testosterone (T) was inhibited because of the down-regulated gnrhr2, gnrhr3, gnrhr4, gnrh3, gnrh2 and er2β in the brain, while 17β-estradiol (E2) increased in 250 µg/L due to up-regulated cyp19a. For males, the promotion of T was directly related to the up-regulation of fshr, 3βhsd, star, cyp11 and cyp17 in the gonad, and eventually led to the increase of E2. The decrease of plasma 11-KT in both sexes could be mainly attributed to the down-regulation of cyp11b and hsd11b. The plasma VTG decreased in females but increased in males, which was in accordance with the down and up regulation of erα and er2β in the females and males, respectively. All these indicated EHDPHP displayed reproductive toxicity on zebrafish in a sex dependent manner. Molecular docking analysis indicated stronger interaction of EHDPHP with the antagonisms of estrogen receptor (ER) and androgen receptor (AR), as well as the agonism of CYP19A1, which further revealed the sex-dependent reproductive toxicity mechanism of EHDPHP. This study highlights the importance of distinguishing males and females in toxicity evaluation of endocrine disruption chemicals.

作为在各种环境介质中经常检测到的有机磷酸酯，2-乙基己基磷酸二苯酯（EHDPHP）对不同性别水生生物的毒性作用仍不清楚。在本研究中，成年斑马鱼暴露于 2.5、50、250 µg/L 的 EHDPHP 21 天，以研究其性别依赖性生殖毒性及其相关机制。EHDPHP 暴露显着抑制了斑马鱼的繁殖，这表现为雌性产卵减少、后代生长发育受抑制。EHDPHP对男性性激素和卵黄素（VTG）的变化影响大于女性。对于女性，由于gnrhr2、gnrhr3、gnrhr4、gnrh3、gnrh2和er2β在脑中，而 17 β-雌二醇 (E2) 由于cyp19a上调而增加 250 µg/L 。对雄性而言，T的促进与性腺中fshr、3βhsd、star、cyp11和cyp17的上调直接相关，最终导致E2的增加。两性血浆 11-KT 的降低主要归因于cyp11b和hsd11b 的下调。女性血浆 VTG 降低，男性升高，与erα和er2β的下调和上调一致分别在女性和男性中。所有这些都表明 EHDPHP 以性别依赖的方式对斑马鱼表现出生殖毒性。分子对接分析表明EHDPHP与雌激素受体（ER）和雄激素受体（AR）的拮抗作用以及对CYP19A1的激动作用更强，进一步揭示了EHDPHP的性别依赖性生殖毒性机制。本研究强调了区分男性和女性在内分泌干扰化学品毒性评估中的重要性。