Effects of Letrozole on Gonad Differentiation of Carp (Cyprinus carpio)
Effects of Letrozole on Gonad Differentiation of Carp (Cyprinus carpio)
Fang Wang, Yong-Fang Jia, Po Wang, Qi-Yan Du and Zhong-Jie Chang*
ABSTRACT
Letrozole (LET) is a triazole-containing drug that can inhibit the activity of cytochrome P450 aromatase, so as to affect the production of estrogen. In the present study, to detect the effects of letrozole on gonad differentiation, 5dph fry of carp were exposed to different concentrations of LET. At 130 dph, sex ratio was recorded. The results showed that continuous exposure to LET induced the changes of sex ratio. High concentration of LET can promote male-biased sex ratio. In order to reveal the molecular mechanism by which LET caused sex reversal, juvenile carp (120dph) were exposed to 0, 5, 25, 125, and 625μg/L LET for 15 days, and the expression profiles of seven gonad differentiation related genes (Cyp19A, Cyp19B, Arα, ERα, Dax, Foxl2, Dmrt1) and gonad histological changes were examined. The results showed that LET could inhibit oocyte growth in female and promote the development of testes in males. For the gonad differentiation related genes, the expression profiles of Cyp19A and Cyp19B show a pattern of increase in short time and low concentration, but decline in long time and high concentration. Arα has a trend of increases, ERα shows downwards trend. Dax and Foxl2 are female-biased genes, their expression profiles show similar trends to Cyp19A in ovary, but downwards trend in testis. Dmrt1 is male-biased genes, it shows a trend of increases in male and female individuals. These findings suggest that continuous exposure to LET may perturb sex differentiation in carp, the molecular mechanism not only involve inhibition of cytochrome P450 aromatase activity, but also the changes of upstream genes in sex differentiation. So, LET can be used as a reagent to control the sex differentiation of carp, but also can be used to disturb gonad differentiation, and then to reveal the molecular mechanism.
To share on other social networks, click on any share button. What are these?
