You are here:
REPRODUCTIVE CHANGES IN THE ESTUARINE FISH CUNNER (TAUTOGOLABRUS ADSPERSUS) EXPOSED TO 17B-ESTRDIOL AND ETHYLINYL ESTRADIOL IN THE LABORATORY
Citation:
Mills, L J., R E. GutjahrGobell, D B. Horowitz, AND G Zaroogian. REPRODUCTIVE CHANGES IN THE ESTUARINE FISH CUNNER (TAUTOGOLABRUS ADSPERSUS) EXPOSED TO 17B-ESTRDIOL AND ETHYLINYL ESTRADIOL IN THE LABORATORY. Presented at Society of Toxicology Conference, Philadelphia, PA, March 19-23, 2000.
Description:
Both 17 -estradiol and ethinyl estradiol are environmental estrogens that have been shown to cause estrogenic effects in fish collected from rivers receiving sewage treatment efHuent. Cunner (Tautogolabrus adspersus) are being studied in our laboratory to evaluate how 17 -estradiol and ethinyl estradiol affect aspects of their reproductive endocrinology and reproductive success. Cunner was selected because this species spawns daily, is common in estuarine areas, is easily obtainable, and is amenable to laboratory holding. In our experiments, fish of both sexes were exposed through subcutaneous implant of the test estrogen in a controlled release matrix (ethyl cellulose and ethoxylated castor oil). In two eight week experiments, male and female laboratory-held cunner were taken from winter conditions, injected with the appropriate treatment, and gradually acclimated to spring spawning conditions over a period of several weeks. Treatments tested in these experiments were uninjected control, matrix-injected control, and 0.05, 0.5 or 2.5 mg/kg concentrations of either 17 -estradiol or ethinyl estradiol. Plasma was taken from a subsample of treated fish over the course of these experiments and analyzed to determine circulating levels of the steroid hormones 17 -estradiol and testosterone, as well as the estrogen- induced yolk protein vitellogenin. Egg production and egg viability were recorded daily over the eight week exposure period. Over the course of the entire experiment, fish treated with the lowest concentration of 17 -estradiol produced more eggs per female than any other treatment. Cunner given the highest concentration of 17 -estradiol produced fewer viable eggs. In the fish treated with ethinyl estradiol, viability of eggs from fish receiving the lowest concentration was half that of controls. Gonadosomatic index (GSI) was determined at the end of each experiment for all surviving fish. Males treated with 17 -estradiol showed a concentration-related increase in GSI, while those treated with ethinyl estradiol exhibited a concentration-related decrease. Overall, results of these experiments suggest that exposure to estrogens can impact the reproductive success of cunner.