Serum Concentrations of Various Environmental Contaminants and Their Relationship to Sex Steroid Concentrations and Phallus Size in Juvenile American Alligators

Department of Zoology, 223 Bartram Hall, University of Florida, Gainesville, Florida 32611, USA.
Archives of Environmental Contamination and Toxicology (Impact Factor: 1.9). 06/1999; 36(4):447-55. DOI: 10.1007/PL00006617
Source: PubMed


Recent studies have reported a number of abnormalities in the hatchling and juvenile alligators of Lake Apopka, FL (USA). These abnormalities include modifications of plasma concentrations of sex steroids in males and females as well as abnormalities in gonadal morphology, gonadal enzyme activity, and steroidogenesis. Embryonic exposure to environmental contaminants in the eggs has been hypothesized to be the causal agent for these changes. However, posthatchling exposure can also contribute to changes in reproductive and endocrine functioning. We have detected serum concentrations of 16 of 18 organochlorine pesticides or metabolites (OCs) and 23 of 28 congener-specific polychlorinated biphenyls (PCBs) examined in juvenile alligators from Lake Apopka, Orange Lake, and Lake Woodruff National Wildlife Refuge. Lake Apopka juveniles had significantly elevated serum concentrations of p,p'-DDE, dieldrin, endrin, mirex, oxychlordane, SigmaDDTs, and SigmaPCBs compared to juveniles from the other lakes. Further, we observed no correlations between serum contaminant concentrations and sex steroid concentrations (estradiol-17beta and testosterone). However, serum testosterone was significantly lower in males from Lake Apopka and Orange Lake compared to Lake Woodruff NWR. We did not observe relationships between phallus size or other body parameters and serum contaminant levels. Phallus size was smaller in males from Lake Apopka even after adjustment for body size. We suggest that the observations previously reported for juvenile alligators-and observed again in this study-are apparently not associated with the current serum levels of the environmental contaminants we measured, but could be due to exposures during embryonic development to these or other pollutants. Future studies must determine if a causal relationship exists between the contaminants found in alligator eggs and abnormalities observed in the hatchlings and persisting in juveniles.

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Available from: Louis J Guillette, Jul 23, 2014
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    • "Photos were captured with Leica Application Suite V3 7.0. The width of the hemipenes of both male and female neonates was measured (mm; Guillette et al. 1999; Newbold 2004). Both hemipenes were measured thrice in ImageJ ( and the average of the six measurements was utilised in the statistical analysis. "
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    • "Florida, USA Egg yolk Sepulveda et al. 2006 Florida, USA Eggs, mature ovaries Sepulveda et al. 2004 Florida, USA Tail muscle Delany et al. 1988 Florida, USA Tail muscle, visceral fat Honeyfield et al. 2008 Florida, USA Blood plasma Guillette et al. 1999 Florida, USA Brain, fat, liver, muscle, stomach content Wheeler et al. 1977 P. CHARRUAU, ET AL. 2 have shown that OCPs can override the temperature effect and cause sex reversal ( male to female ) at intermediate and male producing temperatures in American alli - gator ( A . mississippiensis ) ( Guillette and Milnes 2000 ; Milnes et al . "
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