Gene expression patterns in juvenile American alligators (Alligator mississippiensis) exposed to environmental contaminants

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• 作者：Satomi Kohno ; Dieldrich S. Bermudez ; Yoshinao Katsu ; Taisen Iguchi ; Louis J. Guillette Jr.
• 关键词：Endocrine disruption ; Lake Apopka ; Testosterone ; Estradiol ; Sex steroids ; Sex steroid receptors ; mRNA expression ; Steroidogenesis ; Sexual alteration
• 刊名：Aquatic Toxicology
• 出版年：2008
• 期刊代码：19_0166445x
• 类别：abs
• 出版时间：23 June 2008
• 卷：88
• 期：2
• 页码：95-101
• 文件大小：564 K

摘要

Reproductive and developmental abnormalities have been reported in the American alligator (Alligator mississippiensis) population from Lake Apopka, FL, that is chronically exposed to a complex mixture of environmental contaminants. To begin to understand the molecular mechanisms that could lead to the observed abnormalities of the reproductive and endocrine system, we quantified concentrations of the steroid hormones testosterone (T) and estradiol-17β (E₂) and expression of steroid hormone receptors and genes relating to steroidogenesis in gonadal tissue from juvenile alligators from three lakes in Florida using enzyme immunoassay and quantitative real-time polymerase chain reaction. Alterations of ESR2 (estrogen receptor β) and SF1 (steroidogenic factor 1) mRNA expression in male gonadal tissue, without an observed difference in plasma concentrations of T, from the different lakes, begin to provide insight into potential mechanisms underlying the alterations of the reproductive system previously observed. Likewise, alterations in P450 aromatase and DAX1 (dosage-sensitive sex reversal, adrenal hypoplasia congenita critical region on the X chromosome, gene 1) mRNA expression, with elevated plasma E₂ concentrations in females, provide leads to the potential mechanisms modifying folliculogenesis and ovarian development. The investigation of these genes also helps clarify normal endocrine and reproductive system function in the American alligator.