In vivo formation of (+)-anti-benzo[a]pyrene diol-epoxide-plasma albumin adducts in fish

Benzo[a]pyrene (BaP), a procarcinogenic polycyclic aromatic hydrocarbon (PA H), is bioactivated to BaP diol-epoxides (BPDEs) that can form adducts with DNA and blood proteins. We report here for the first time the in vivo form ation of adducts between BPDE and plasma albumin (Alb) from two fish specie s experimentally exposed to BaP. Brook trout (Salvelinus fontinalis) receiv ed either a single i.p. dose (10 mg/kg) or two separate i.p. doses (25 mg/k g; 7 days apart) of BaP, and blood was collected 2 (single exposure) or 3 ( multiple exposure) days post-treatment. Arctic charr (Salvelinus alpinus) r eceived 10 i.p. doses (3 mg/kg; a single dose every 6 days), and blood was collected 2 days after the second, sixth, and 10th injections. BPDE-Alb add ucts were measured by an improved HPLC/fluorescence method developed to det ect and quantify BaP-tetrols released after acid hydrolysis of adducted Alb . HPLC/fluorescence chromatograms of Alb from BaP-treated fish revealed onl y BaP-tetrol I-1, thus indicating the formation of adducts exclusively via the (+)-anti-BPDE metabolite. Levels of (+)-anti-BPDE-Alb adduct ranged fro m 0.68 to 19.6 ng of tetrol I-1 per gram of Alb. Notably, adduct level was not related to BaP dose and there was no accumulation of adducts with repea ted exposure, which may indicate a very short half-life (< 2 days) of plasm a Alb in fsh. The data suggest that BPDE-Alb adducts in fish could be usefu l as a non-destructive biomarker of recent exposure to bioactivated BaP. (C ) 2000 Elsevier Science Ltd. All rights reserved.