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THE PATHOBIOLOGY OF 17B-ESTRADIOL IN SUMMER FLOUNDER, PARALICHTYS DENTATUS
Citation:
Horowitz, D B., G R. Gardner, R GutjahrGobell, L J. Mills, R Haebler, AND G Zaroogian. THE PATHOBIOLOGY OF 17B-ESTRADIOL IN SUMMER FLOUNDER, PARALICHTYS DENTATUS. Presented at 25th Annual Eastern Fish Health Workshop, Plymouth MA, April 10-14, 2000.
Description:
Estradiol has been shown to cause increased vitellogenin (VtG) concentrations in male fish. The intent of this study was to evaluate the pathobiology associated with exposure to 17 -estradiol (E2) on liver, gonad, and kidney tissues of summer flounder, Paralichthys dentatus. Juvenile male summer flounder were treated twice, two weeks apart, via injection into a dorsal sinus with concentrations of 0.1, 1.0, or 10.0 mg/kg E2. E2 was incorporated into coconut oil to effect a slow release mechanism. control fish were injected with the carrier coconut oil and handled in the same manner as the dosed ones. At 4 weeks after initial injection, a hyaline substance had accumulated in a dose-dependent manner within the liver, testes, and kidneys of the 17 -estradiol treated fish. Excessive hyaline accumulations produced hepatocytic hypertrophy in the liver and injury to glomeruli and tubules in the kidney. These hyaline accumulations contributed to mortalities observed in the 10.0 mg/kg treatment. In the testes, the hyaline substance was observed in stromal elements of seminiferous tubules and ducts, and testicular development was impaired. The hyaline-like material stained positively with Periodic Acid Schiff, both with and without diastase digestion. Immunohistochemical staining for presence of VtG was positive in 17 -estradiol treated flounder livers, gonads, and kidneys and yielded no positive staining in the control tissues.