Effects of Bis(2-ethylhexyl) Phthalate on Sex Hormones of Common Carp (Cyprinus carpio) and the Protection of Zinc

Abstract

DEHP is a priority pollutant and sex hormone endocrine disruptor, which can disturb all physiological processes. In this study, bis(2-ethylhexyl)phthalate (DEHP) toxicities to common carps were investigated using multiple sex hormones, such as testosterone (T), 11-ketotestosterone (11-KT), 17β -estradiol (E2), and progesterone (P), and the precursor of sex steroids Chl, aromatase activity, as well as and the protection effects of zinc. The results showed that serum testosterone concentration increase in male common carps (Cyprinus carpio) exposed to 5.5, 10.5, 15.5, and 20.5 mg/L when compared to control (p < 0.05), but, when pretreated with zinc gluconate solution, the serum testosterone levels decreased compared with control group (p < 0.05); serum 11-KT concentrations were significantly elevated in the 20.5 mg/L DEHP group when comparatively exposed to 5.5 mg/L DEHP in males (p < 0.05), zinc exposure could restrain the increase of the concentration of 11- KT; 17β-estradiol activity was strongly reduced by DEHP and DEHP-induced progesterone levels decreasing in both male and female common carps with the increased DEHP concentration (p < 0.05), zinc can depress the decrease of E2 and progesterone levels partly. DEHP caused significant decrease of cholesterol in serum when compared with control group (p < 0.05), no significant differences in serum cholesterol concentration of male and female common carps (p < 0.05), and continuous incubation time induced a further decrease in serum cholesterol in common carps; the brain AA differed significantly with the different DEHP concentration. Males and females common carps had a significantly higher activity while non-treatment with DEHP, and males and females present lower activity when treated with 20.5 mg/L. Therefore, DEHP can affect T, 11-KT, E2, P, Chl, and AA levels, and zinc has antagonism to toxicity of DEHP.

Keywords:

• DEHP
• sex hormone
• common carp
• zinc

This research was supported by the Foundation of Key Laboratory of Marine Biotechnology of JiangSu, China (Project No. 2005HS008), and the Foundation of Social Development Planning of Lianyungang City of Jiangsu, China (Project No. SH0809). We thank Chunxia Lv and Huangli for exemplary technical assistance and Shaocong Han for valuable support on statistical analysis.