title: Gonadotropin and estrogen responses in freshwater turtle (Chrysemys picta) from Cape Cod, Massachusetts.
abstract: As a result of chemical waste disposal on the Massachusetts Military Reservation, a Superfund site on Cape Cod, MA, contaminated groundwater plumes have formed. These plumes are of concern due to the widespread use of groundwater wells as a drinking water source by the local population. Prior observations on a sentinel species Chrysemys picta field-trapped from ponds on Cape Cod suggested deficits in reproductive processes including lower levels of vitellogenin, estradiol-17beta, oviduct weights, and oocyte numbers in females and lower testicular weight and sperm count in males. Possible loci in the hypothalamic-pituitary-gonadal-liver axis at which xenobiotics may act were determined in turtles trapped from Moody Pond (a test site) and Washburn Pond (a reference site). Specifically, gonadotropin and estrogen responses were assessed using plasma steroids and vitellogenin as markers. Basal vitellogenin levels were significantly lower in Moody Pond females; however, vitellogenin responses to estradiol-17beta were the same in both groups, indicating a normal hepatic response to estrogen. In contrast, estradiol-17beta secretion was not stimulated by gonadotropin in Moody Pond females, compared to Washburn animals. Basal plasma testosterone and the response to gonadotropin in males were similar, although steroid levels in Moody Pond animals were slower to return to baseline after gonadotropin injection. The results suggest that a low-level mixture of xenobiotic contaminants may interfere with the steroid metabolic pathways in turtles exposed to the test site, but not the reference site, environment.
authors.affiliation: Department of Biology, Faculty of Science, Chulalongkorn University, Phyathai Road, Pathumwan, Bangkok 10330, Thailand. nkitana@bu.edu
authors.forename: Noppadon
authors.initials: N
authors.lastname: Kitana
authors.forename: Wichase
authors.initials: W
authors.lastname: Khonsue
authors.forename: Seung Jae
authors.initials: SJ
authors.lastname: Won
authors.forename: Valentine A
authors.initials: VA
authors.lastname: Lance
authors.forename: Ian P
authors.initials: IP
authors.lastname: Callard
mesh_terms: D000818:Animals; D004784:Environmental Monitoring; D004958:Estradiol / Q000097:blood* / Q000494:pharmacology; D004967:Estrogens / Q000378:metabolism*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D006062:Gonadotropins / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008404:Massachusetts; D010053:Ovary / Q000187:drug effects; D013737:Testis / Q000187:drug effects; D013739:Testosterone / Q000097:blood; D014426:Turtles / Q000097:blood / Q000378:metabolism*; D014819:Vitellogenins / Q000378:metabolism; D014874:Water Pollutants, Chemical
chemical_list: D004967:Estrogens; D006062:Gonadotropins; D014819:Vitellogenins; D014874:Water Pollutants, Chemical; D013739:Testosterone; D004958:Estradiol; D005640:Follicle Stimulating Hormone