The oral bioavailability, pharmacokinetics and biotransformation of 9-hydroxybenzo[a]pyrene in the American lobster, Homarus americanus

Abstract

The pharmacokinetics of [ 3H]-9-hydroxy-benzo[a]pyrene (9-OH-BaP) were examined after single intrapericardial (IV) or oral doses to intermolt American lobsters, Homarus americanus. A three-compartment model best described the disposition of parent 9-OH-BaP in the hemolymph after IV administration. The major metabolite found in hemolymph 8 h after administration, BaP 9-sulfate, reached its peak concentration at one day after the dose. BaP 9-sulfate was eliminated from hemolymph more rapidly than 9-OH-BaP or BaP9-β-D-glucoside, which were present in all hemolymph samples at all times. The oral bioavailability (F) for 9-OH-BaP, estimated from the area under concentration-time curve (AUC), ranged from 3.4 to 14.3%. In all treated lobsters, < 10% dose was left in tissues at 10 days. PAPS-sulfotransferase (ST) and UDP-glucosyltransferase (UDP-GT) activities were detected in the intestinal mucosa as well as in the antennal gland (ST) and the hepatopancreas (UDP-GT). These studies showed that 9-OH-BaP and its sulfate and glucoside conjugates were excreted from lobster tissues more rapidly than BaP, but were retained by the lobster for longer than the smaller, less lipophilic phenolic compounds, phenol and β-naphthol and their metabolites.