Effects of Progesterone on the reproductive physiology in zebrafish

Recent studies have investigated that the synthetic progestins may lead to health issues to the aquatic organisms. Progesterone is a steroidal progestin and has been used as a contraceptive drug, which is detected in the aquatic ecosystem. However, the potential effects of progesterone on the fish reproduction are largely unclear. Here, we tested the effects of progesterone on the fish reproductive and endocrine systems. Adult zebrafish were exposed to progesterone for 10 days at environmental concentrations. The production of eggs was reduced in the exposed fish, and the circulating concentrations of estradiol (E2) and testosterone (T) in female fish or 11-keto testosterone (11-KT) in male fish were significantly diminished. Our results suggested that progesterone may cause adverse health effects on fish by disrupting the endocrine system, and short-term exposure to progesterone could overt affect the fish reproduction.