| Developmental Abnormalities of the Gonad and Abnormal Sex Hormone Concentrations in Juvenile Alligators from Contaminated and Control Lakes in Florida Louis J. Guillette Jr.,
1,2
Timothy S. Gross,
2
Greg R. Masson,
1,3
John M. Matter,
1
H. Franklin Percival,
4
and Allan R. Woodward
5
1
Department of Zoology and
2
BEECS Reproductive Analysis Laboratory, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL 32611 USA;
3
U.S. Fish and Wildlife Service, Contaminants Branch, Brunswick, GA 31520 USA;
4
National Biological Survey, Florida Cooperative Fish and Wildlife Research Unit, Department of Wildlife and Range Sciences, University of Florida, Gainesville, FL 32611 USA;
5
Florida Game and Fresh Water Fish Commission, Gainesville, FL 32601 USA Abstract
The reproductive development of alligators from a contaminated and a control lake in central Florida was examined. Lake Apopka is adjacent to an EPA Superfund site, listed due to an extensive spill of dicofol and DDT or its metabolites. These compounds can act as estrogens. Contaminants in the lake also have been derived from extensive agricultural activities around the lake that continue today and a sewage treatment facility associated with the city of Winter Garden, Florida. We examined the hypothesis that an estrogenic contaminant has caused the current failure in recruitment of alligators on Lake Apopka. Supporting data include the following: At 6 months of age, female alligators from Lake Apopka had plasma estradiol-17ß concentrations almost two times greater than normal females from the control lake, Lake Woodruff. The Apopka females exhibited abnormal ovarian morphology with large numbers of polyovular follicles and polynuclear oocytes. Male juvenile alligators had significantly depressed plasma testosterone concentrations comparable to levels observed in normal Lake Woodruff females but more than three times lower than normal Lake Woodruff males. Additionally, males from Lake Apopka had poorly organized testes and abnormally small phalli. The differences between lakes and sexes in plasma hormone concentrations of juvenile alligators remain even after stimulation with luteinizing hormone. Our data suggest that the gonads of juveniles from Lake Apopka have been permanently modified in ovo , so that normal steroidogenesis is not possible, and thus normal sexual maturation is unlikely. Key words: alligators, estrogens, gonadal abnormalities, reptiles, testosterone. Environ Health Perspect 102:680-688 (1994) Address correspondence to L. J. Guillette, Jr., Department of Zoology, University of Florida, Gainesville, FL 32611 USA. The St. John's Water Management District and the Biotechnologies for the Ecological, Evolutionary and Conservation Sciences (BEECS) Program, University of Florida, provided partial funding for this project. This work would not have been possible without a group of state, federal, and university biologists and volunteers. Especially, we thank Dennis David and other personnel of the Florida Game and Freshwater Fish Commission for their long-term support of our projects. We thank Joe Hill and Ken Rice and other volunteers for field assistance while collecting the eggs used for this study ; Denise Gross for advice and assistance with the care of neonatal alligators ; D. Crain and C. Cox for assistance with the hormonal assays ; A. Cree and several anonymous reviewers for valuable comments on the manuscript ; Jack Brown for providing facilities and care during the alligator growth study ; and Leon Rhodes for providing assistance and allowing us to work on the Lake Woodruff National Wildlife Refuge. Use of manufacturers' names does not imply endorsement by any of the authors or their respective institutions and agencies. Received 24 January 1994 ; accepted 17 May 1994.
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