title: Is serum gamma-glutamyltransferase an exposure marker of xenobiotics? Empirical evidence with polycylic aromatic hydrocarbon.
abstract: BACKGROUND
  We recently hypothesized that serum gamma-glutamyltransferase (GGT), within its reference range, predicts many diseases as a biomarker for background exposure to various xenobiotics. Even though normal serum GGT was associated with xenobiotics having very long half-lives (heavy metals, dioxin, or organochlorine pesticides), it was unknown whether GGT was associated with xenobiotics with short half-lives, including polycyclic aromatic hydrocarbons (PAHs), well known carcinogens.
  
  
  METHODS
  Among 1256 adult participants in the National Health and Nutrition Examination Survey (NHANES) 2003-2004, urinary metabolites of PAH (monohydroxy-PAH), and serum GGT were measured. We selected the 10 monohydroxy-PAHs (OH-PAHs) for which at least 90% of participants had concentrations greater than the limit of detection.
  
  
  RESULTS
  Among the 10 OH-PAHs, eight had significant positive correlations with serum GGT. These correlations were similarly observed in men and women, and in individuals under 60 years of age. Unlike serum GGT, alanine aminotransferase, another liver enzyme, was not associated with OH-PAHs.
  
  
  CONCLUSIONS
  Taken together with the previous epidemiological evidence, the associations of serum GGT with OH-PAHs reinforce the concept that serum GGT is a marker for various environmental pollutants encountered at background levels in the general population.
authors: Department of Preventive Medicine and Health Promotion Research Center, School of Medicine, Kyungpook National University, Daegu, Korea. lee_dh@knu.ac.kr
authors: Duk-Hee
authors: DH
authors: Lee
authors: David R
authors: DR
authors: Jacobs
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000410:Alanine Transaminase / Q000097:blood; D004785:Environmental Pollutants / Q000378:metabolism / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism / Q000652:urine*; D015262:Xenobiotics / Q000652:urine; D005723:gamma-Glutamyltransferase / Q000097:blood*
chemical_list: D004785:Environmental Pollutants; D011084:Polycyclic Aromatic Hydrocarbons; D015262:Xenobiotics; D005723:gamma-Glutamyltransferase; D000410:Alanine Transaminase