PARENT SESSION
PT1 - Aquatic Toxicology
Tuesday, 19 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P517) effects of Dietary and Static Renewal Exposure of Androstenedione on Female Mosquitofish, Gambusia affinis.
Stanko, Jason*,1, Dean, Jessica1, Angus, Robert1, 1 University of Alabama at Birmingham, Birmingham, AL, USA
ABSTRACT- The Fenholloway River, Taylor County, FL receives effluent from a paper mill and female mosquitofish, Gambusia holbrooki, in the river are masculinized. Recently, androstenedione was identified as one of the potentially bioactive constituents of Fenholloway River water. In this experiment, female G. affinis were exposed through dietary administration to four concentrations (0.7, 7, 70, and 700 mg hormone/gram of food) of 4-androsten-3, 17-dione (ASD) in an effort to reproduce the effects observed in the Fenholloway River. Female G. affinis were also exposed by direct addition to the water of 0.14, 1.4, 14.0, 140.0 and 350 nM ASD in a static renewal assay for comparison to dietary exposure. No significant changes in fin ray morphology were detected in the dietary experimental groups. There were no significant differences in gonad mass or liver mass between the dietary experimental groups and control groups, nor was there a difference in the number of late stage follicles. Vitellogenin expression, determined by Western Blot analysis, in each dietary experimental group was significantly greater than that of the positive controls, but not the negative controls. Female mosquitofish in the 140.0 and 350 nM static renewal groups exhibited morphological masculinization as measured by anal fin elongation. These females also had a reduced total mass and standard length compared to controls. However, no significant changes were observed in gonadosomatic or hepatosomatic indices between experimental groups and controls. Histological analysis and vitellogenin expression are currently being conducted. These data indicate that direct exposure to androstenedione through the water results in morphological masculinization of female mosquitofish while dietary exposure does not appear to have a masculinizing effect. This work supported by EPA Grant R826130-01-0.
Key words: Endocrine disruption, Reproductive toxicology, Androstenedione, Environment