title: Associations between complex OHC mixtures and thyroid and cortisol hormone levels in East Greenland polar bears.
abstract: The multivariate relationship between hair cortisol, whole blood thyroid hormones, and the complex mixtures of organohalogen contaminant (OHC) levels measured in subcutaneous adipose of 23 East Greenland polar bears (eight males and 15 females, all sampled between the years 1999 and 2001) was analyzed using projection to latent structure (PLS) regression modeling. In the resulting PLS model, most important variables with a negative influence on cortisol levels were particularly BDE-99, but also CB-180, -201, BDE-153, and CB-170/190. The most important variables with a positive influence on cortisol were CB-66/95, α-HCH, TT3, as well as heptachlor epoxide, dieldrin, BDE-47, p,p'-DDD. Although statistical modeling does not necessarily fully explain biological cause-effect relationships, relationships indicate that (1) the hypothalamic-pituitary-adrenal (HPA) axis in East Greenland polar bears is likely to be affected by OHC-contaminants and (2) the association between OHCs and cortisol may be linked with the hypothalamus-pituitary-thyroid (HPT) axis.
authors.affiliation: University of Aarhus, Faculty of Science & Technology, Department of Bioscience, Roskilde, Denmark. thbe@dmu.dk
authors.forename: T Ø
authors.initials: TØ
authors.lastname: Bechshøft
authors.forename: C
authors.initials: C
authors.lastname: Sonne
authors.forename: R
authors.initials: R
authors.lastname: Dietz
authors.forename: E W
authors.initials: EW
authors.lastname: Born
authors.forename: D C G
authors.initials: DC
authors.lastname: Muir
authors.forename: R J
authors.initials: RJ
authors.lastname: Letcher
authors.forename: M A
authors.initials: MA
authors.lastname: Novak
authors.forename: E
authors.initials: E
authors.lastname: Henchey
authors.forename: J S
authors.initials: JS
authors.lastname: Meyer
authors.forename: B M
authors.initials: BM
authors.lastname: Jenssen
authors.forename: G D
authors.initials: GD
authors.lastname: Villanger
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry / Q000378:metabolism; D000375:Aging / Q000097:blood / Q000378:metabolism; D000818:Animals; D004784:Environmental Monitoring / Q000379:methods* / Q000706:statistics & numerical data; D004785:Environmental Pollutants / Q000032:analysis* / Q000493:pharmacokinetics; D005260:Female; D006197:Hair / Q000737:chemistry / Q000378:metabolism; D006846:Hydrocarbons, Halogenated / Q000032:analysis* / Q000493:pharmacokinetics; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D015999:Multivariate Analysis; D012044:Regression Analysis; D013963:Thyroid Hormones / Q000097:blood*; D013974:Thyroxine / Q000097:blood; D014018:Tissue Distribution; D014284:Triiodothyronine / Q000097:blood; D001503:Ursidae / Q000097:blood / Q000378:metabolism*
chemical_list: D004785:Environmental Pollutants; D006846:Hydrocarbons, Halogenated; D013963:Thyroid Hormones; D014284:Triiodothyronine; D013974:Thyroxine; D006854:Hydrocortisone