Effects Of Two Pesticide EDCs On Serum Sex Steroids, TSH And T₃ In Juvenile Male Carassius Auratus

Endocrine disruption of low-dose alachlor and atrazine exposure to Carassius auratus was studied. In this study, effects on serum sex steroids (17β-estradiol (E2),testosterone (T)),thyroid stimulating hormone(TSH) and tri-iodothyronine(T3) was measured, with the purpose to explore the mechanism, dose-effect relationship and biomarker. Juvenile male Carassius auratus were exposed to low-dose (0⁰.500mg·L^-1) alachlor and (0³mg·L^-1) atrazine for 60 days, concentrations of serum E2, T, TSH, T3 were determined by RIA respectively.Compared with the controls, the results indicated that:1)Levels of serum E2 significantly (p<0.05) increased in the alachlor treatments (0.004, 0.016, 0.062, 0.250, 0.500mg·L^-1) and in the atrazine treatments (0.023, 0.094, 1.500, 3.000mg·L^-1). They had similar effects on serum E2 and both enhanced the levels of serum E2;2)No obvious effects on the concentrations of serum T in the alachlor treatments (0..001,0.004, 0.016, 0.062 mg·L^-1) or in all treatments were observed, but significantly (p<0.05) decline in the alachlor treatments (0.250, 0.500mg·L^-1);3) E2/T was increased along with the doses of alachlor and atrazine raise, and significantly in all treatments of alachlor and in the atrazine treatments (1.500, 3.000mg·L^-1). These indicated that both alachlor and atrazine had feminization effects on the fish;3)TSH was significantly (p<0.05) increased in the alachlor treatment (0.250 mg·L^-1) and significantly (p<0.05) depressed when fish were exposed to high doses of atrazine (0.094, 1.500, 3.000 mg·L^-1) and no significant difference in other treatments of both pesticide;4)T3 increased significantly (p<0.05) in the alachlor treatments (0.004, 0.062, 0.250, 0.500 mg·L^-1) and in the highest dose atrazine treatment (3.000mg·L^-1), but showed no significant differences in low-dose treatments (0.006, 0.023, 0.094, 0.375, 1.500mg·L^-1).These results suggested that both alachlor and atrazine have effects on the level of serum sex steroids, TSH and T3 in juvenile male Carassius auratus, and significant on E2, which can be a biomarker of evaluation of endocrine disruption.