Pharmacokinetics of 2-naphthol following intrapericardial administration, and formation of 2-naphthyl- beta --glucoside and 2-naphthyl sulphate D in the American lobster, Homarus americanus

Abstract

1. Following a 0 25-mg kg intrapericardial dose of the phenolic compound, 2- naphthol, to the American lobster, Homarus americanus, a two-compartment model best described the disposition of parent \ [C]-2-naphthol in the haemolymph. Male and female lobsters had similar alpha -phase half lives of 26 19 min (mean SD, n 4) and 29 15 min respectively. The beta -phase half lives were significantly longer in males,63 9 30 9 h, thanin females, 30 6 6 8 h (p 0 05). The total body clearance for females was 26 4 6 5 ml h kg and was higher than that of males, 11 1 5 9 ml h kg (p 0 05). 2. 2-Naphthol was converted to 2-naphthyl- beta -D-glucoside (major metabolite) and 2- naphthyl sulphate (minor metabolite) such that at 24 h 39-60 6% of the radioactivity in haemolymph was 2-naphthyl- beta -D-glucoside, 38 6-58 9% 2-naphthol and 0 5-4% 2- naphthyl sulphate. 3. The2-naphthol-derivedradioactivity was 99%boundtohaemolymphproteinsat 1 min and 90% bound at 1 day after the dose, indicating that both 2-naphthol and 2- naphthyl- beta -D-glucoside were highly protein bound. 4. 2-Naphthyl- beta -D-glucoside was slowly eliminated from haemolymph in both males and females, with elimination half lives of 34-78 h. 2-Naphthyl- beta -D-glucoside was the major metabolite in urine samples collected at 5 days after the dose. Hepatopancreas and antennal gland contained glucosidase activities, and the long half life of 2-naphthyl- beta -Dglucoside could be explained by conjugation-deconjugation cycling. 5. 2-Naphthyl sulphate was eliminated from haemolymph with a half-life 10 h and was excreted in urine.