Effects of polychlorinated biphenyls and lipemia on serum analytes

Abstract

Twelve serum analytes [triglycerides, cholesterol, total and conjugated bilirubin, high-density-lipoprotein cholesterol (HDL-C), alkaline phosphatase (AP), gammaglutamyl transferase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), beta-glucuronidase (beta-glu), alanine aminopeptidase (AAP), and 5'-nucleotidase (5'nuc)] were measured to investigate their correlation with exposure to polychlorinated biphenyls (PCBs) and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT). The relationship between serum lipids, lipophilic toxicants, and the analytes was also evaluated. The beta-glu, 5'nuc, triglycerides, cholesterol, and total bilirubin correlated positively and significantly with log concentrations of serum total PCBs and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), a metabolite of DDT. The more highly chlorinated PCBs (Aroclor 1260) had significant, positive correlations with several serum analytes, but the less chlorinated PCBs (Aroclor 1242) correlated significantly and negatively only with HDL-cholesterol. Triglyceride- and cholesterol-rich lipoproteins were added to serum to determine the effects of lipids on these assays. Several were spuriously elevated. AP and beta-glu were not affected by lipoprotein addition with the methods used in this study. AAP was increased significantly only at triglyceride concentrations exceeding 400 mg/dl. Lipoproteins may be elevated because of deranged lipid metabolism in response to PCBs, or PCBs may be elevated because elevated lipoproteins are present, as in familial triglyceridemia, a relatively common dyslipoproteinemia. Because this relationship is not well understood with respect to cause and effect, we propose the further use in epidemiological investigations of assay methods that are little affected by blood lipids yet are correlated with PCB concentrations. Congener-specific quantification of PCBs would help elucidate the effects of PCBs on assays used to monitor health effects.