Meeting Abstract

46.3  Monday, Jan. 5  Assessment of short-term and long-term exposures of non-steroidal estrogen, triclosan in western male mosquitofish, Gambusia affinis RAUT, Samiksha*; ANGUS, Robert; Univ. of Ala. at Birmingham, Birmingham; Univ. of Ala. at Birmingham, Birmingham samiksha@uab.edu

Triclosan (TCS) is an antibacterial agent used in a variety of personal care and industrial products such as soap, shampoo, and textile goods. TCS and its environmentally transformed derivative, methyl-TCS has been detected in waters receiving effluent from wastewater treatment plants. The molecular structure of TCS resembles that of other non-steroidal estrogens. Furthermore, it has been shown to displace [(3)H] estradiol from estrogen receptors in human breast cancer cell lines, suggesting a role in the interference of normal endocrine functions. However, the endocrine disrupting potential of TCS has not been well studied. We hypothesize that TCS acts as an estrogen and an endocrine disrupting agent in fish. To test this hypothesis, we exposed mature male western mosquitofish,Gambusia affinis to TCS and measured vitellogenin induction as a biomarker of endocrine disruption. In the present study, mature male mosquitofish were exposed for two weeks to various concentrations of TCS (10nM, 50 nM, 350 nM, and 700nM) using the static renewal method. Ethynylestradiol (10nM) was used as a positive control. At the end of the exposure period, livers were isolated and vitellogenin mRNA expression was determined by real time-PCR analysis. Induction of vitellogenin mRNA expression was seen in the 700 nM TCS treatment group. We also measured standard length, weight, hepatosomatic and gonadosomatic indices in these treatment groups and found no significant differences between treatment groups. These results suggest that TCS acts as a weak estrogen as compared to ethynylestradiol and an endocrine disruptor in aquatic organisms. We are currently investigating long-term effect of TCS exposure on vitellogenin induction and sperm production in mature male western mosquitofish, Gambusia affinis.