title: A Preliminary Link between Hydroxylated Metabolites of Polychlorinated Biphenyls and Free Thyroxin in Humans.
abstract: BACKGROUND
  Polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (HO-PCBs) interfere with thyroid hormone action both in vitro and in vivo. However, epidemiologic studies on the link between PCB exposure and thyroid function have yielded discordant results, while very few data are available for HO-PCBs.
  
  
  OBJECTIVE
  Our study aimed at investigating the relationship between clinically available markers of thyroid metabolism and serum levels of both PCBs and HO-PCBs.
  
  
  METHODS
  In a group of 180 subjects, thyroid-stimulating hormone (TSH) and free thyroxin (fT4), 29 PCBs (expressed both in lipid weight and in wet weight) and 18 HO-PCBs were measured in serum.
  
  
  RESULTS
  In regression models, adjusted for gender, age, current smoking behavior, BMI and total lipid levels, serum levels of 3HO-PCB118 and 3HO-PCB180, and PCB95(lw), PCB99(lw) and PCB149(lw) were independent, significant predictors of fT4. A stepwise, multiple regression with gender, age, current smoking behavior, BMI and total lipid levels and all five previously identified significant compounds retained age, BMI, PCB95(lw), PCB99(lw) and 3HO-PCB180 as significant predictors of fT4. TSH levels were not predicted by serum levels of any of the PCBs or HO-PCBs.
  
  
  CONCLUSIONS
  Our study indicates that in vivo, circulating fT4 levels can be linked to serum levels of several PCBs and hydroxylated PCB metabolites.
authors.affiliation: Department of Endocrinology, Diabetology and Metabolism, Antwerp University Hospital, University of Antwerp, Wilrijkstraat 10, Edegem 2650, Belgium. eveline.dirinck@uza.be.
authors.forename: Eveline
authors.initials: E
authors.lastname: Dirinck
authors.affiliation: Toxicology Centre, University of Antwerp, Wilrijk 2610, Belgium. alindirtu@yahoo.com.
authors.forename: Alin C
authors.initials: AC
authors.lastname: Dirtu
authors.affiliation: Toxicology Centre, University of Antwerp, Wilrijk 2610, Belgium. malarvannan.govindan@uantwerpen.be.
authors.forename: Govindan
authors.initials: G
authors.lastname: Malarvannan
authors.affiliation: Toxicology Centre, University of Antwerp, Wilrijk 2610, Belgium. adrian.covaci@uantwerpen.be.
authors.forename: Adrian
authors.initials: A
authors.lastname: Covaci
authors.affiliation: Department of Clinical Pharmacology, Antwerp University Hospital, University of Antwerp, Edegem 2650, Belgium. philippe.jorens@uza.be.
authors.forename: Philippe G
authors.initials: PG
authors.lastname: Jorens
authors.affiliation: Department of Endocrinology, Diabetology and Metabolism, Antwerp University Hospital, University of Antwerp, Wilrijkstraat 10, Edegem 2650, Belgium. luc.van.gaal@uza.be.
authors.forename: Luc F
authors.initials: LF
authors.lastname: Van Gaal
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D005260:Female; D006801:Humans; D006900:Hydroxylation; D008297:Male; D008875:Middle Aged; D011078:Polychlorinated Biphenyls / Q000097:blood* / Q000493:pharmacokinetics; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology; D013961:Thyroid Gland / Q000378:metabolism; D013963:Thyroid Hormones / Q000097:blood; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*; D055815:Young Adult
chemical_list: D013963:Thyroid Hormones; C500336:2,2',4,4',5-pentachlorobiphenyl; D013972:Thyrotropin; D011078:Polychlorinated Biphenyls; D013974:Thyroxine
keywords: endocrine disrupters; human; hydroxylated polychlorinated biphenyls; polychlorinated biphenyls; thyroid function