A comparison of the binding and distribution of benzo[a]pyrene in human and rat serum.
Uptake and distribution of benzo[a]pyrene (B[a]P) in human and rat serum were studied by incubation, gel filtration and ultracentrifugation. A maximum uptake of 230 and 120 micrograms B[a]P/ml was found for human and rat serum, respectively. Of the B[a]P uptake about 1% was irreversibly bound to serum constituents from both species. The uptake of B[a]P by the lipoproteins was 90-95% and 80-85% for human and rat serum, respectively, the remainder being bound to albumin. In human serum B[a]P was mainly associated with low density lipoproteins (44-47%) while in rat serum with high density lipoproteins (40-54%). However, the distribution of B[a]P between the different lipoprotein fractions showed a high correlation with the concentration of cholesterol for both species. The present results demonstrate a serum uptake capacity of B[a]P for both species which exceeds any known occupational exposure. The extensive association between B[a]P and lipoproteins may have implications for the availability of B[a]P for metabolizing organs, an area which should be further investigated. As far as the total serum uptake and distribution of B[a]P are concerned, the rat seems to be an acceptable animal model for extrapolation of in vivo results to man.
Department of Pharmacology and Toxicology, Faculty of Medicine, University of Trondheim, Regional Hospital, Norway.
K
K
Aarstad
R
R
Toftgård
O G
OG
Nilsen
D000328:Adult; D000818:Animals; D001564:Benzo(a)pyrene / Q000097:blood*; D006801:Humans; D007700:Kinetics; D008074:Lipoproteins / Q000097:blood* / Q000302:isolation & purification; D008297:Male; D011485:Protein Binding; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity
D008074:Lipoproteins; D001564:Benzo(a)pyrene