245 Environmental Contaminants and Health: New Lessons From Wildlife

Thursday, November 5, 2009: 9:20 AM
Kohlberg (Camino Real Hotel)
Louis J. Guillette Jr. , Department of Biology, UNIVERSITY OF FLORIDA, Gainesville, FL
Many chemicals introduced into the environment by humans adversely affect embryonic development of animals, including humans. It has been hypothesized that many developmental alterations are due to the endocrine disruptive effects of various environmental contaminants as the endocrine system exhibits an organizational effect on the developing embryo. Thus, a disruption of normal hormonal signals can permanently modify the organization and future function of the reproductive system.

We have performed a number of experimental studies exposing developing embryos to various persistent and non-persistent pesticides. Using the American alligator (Alligator mississippiensis, egg dosing studies with pesticides have produced alterations in gonadal steroidogenesis, secondary sex characteristics and gonadal anatomy that are similar to those reported in wild populations exposed to agricultural pesticides. We have found alteration in the structure of the developing ovarian follicle, including modification in the thecal and granulosa cells of the ovary. These experimental studies have begun to provide the causal relationships between embryonic pesticide exposure and reproductive abnormalities that have been lacking in pure field studies of wild populations. Moreover, as the gene expression level, the changes we have observed in wildlife are similar to changes described in the human ovary that are associated with several prevalent diseases (e.g., premature ovarian failure, polycyctic ovary syndrome, polyovular follicle syndrome). An understanding of the developmental consequences of endocrine disruption in wildlife can lead to new indicators of exposure and a better understanding of the most sensitive life stages and the consequences of exposure during these periods for wildlife and humans.

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