title: Gene expression patterns in juvenile American alligators (Alligator mississippiensis) exposed to environmental contaminants.
abstract: 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-17beta (E(2)) 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 beta) 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 E(2) 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.
authors.affiliation: Department of Zoology, 223 Bartram Hall, PO Box 118525, University of Florida, Gainesville, FL 32611-8525, USA. kohno@zoo.ufl.edu
authors.forename: Satomi
authors.initials: S
authors.lastname: Kohno
authors.forename: Dieldrich S
authors.initials: DS
authors.lastname: Bermudez
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Katsu
authors.forename: Taisen
authors.initials: T
authors.lastname: Iguchi
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Guillette
mesh_terms: D000489:Alligators and Crocodiles / Q000235:genetics* / Q000378:metabolism*; D000818:Animals; D001141:Aromatase / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D004781:Environmental Exposure; D047629:Estrogen Receptor beta / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects*; D006728:Hormones / Q000097:blood; D008297:Male; D010053:Ovary / Q000737:chemistry / Q000187:drug effects; D054339:Steroidogenic Factor 1 / Q000235:genetics; D013737:Testis / Q000737:chemistry / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D004268:DNA-Binding Proteins; D047629:Estrogen Receptor beta; D006728:Hormones; D054339:Steroidogenic Factor 1; D014874:Water Pollutants, Chemical; D001141:Aromatase