Dose- and time-dependent formation of biliary benzo[a]pyrene metabolites in the marine flatfish dab (Limanda limanda).
ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) are abundant pollutants, and many PAHs are carcinogenic, but only after metabolic activation. Benzo[a]pyrene (BaP) is among the most carcinogenic PAHs. The dose and time response of two enzymes involved in BaP metabolism and the amounts of BaP metabolites excreted into the bile were evaluated in an experiment with dab (Limanda limanda). Ninety dab were exposed orally to one of five doses of BaP (0, 0.08, 0.4, 2, or 10 mg/kg) and sampled at 3, 6, or 12 d after exposure. None of the doses studied caused significant induction of either microsomal ethoxyresorufin-O-deethylase (EROD). which reflects cytochrome P450 1A (CYP1A) activity, or cytosolic glutathione-S-transferase activity (GST). Concentrations of biliary BaP metabolites significantly increased with dose and significantly decreased with time after exposure. It is concluded that biliary BaP metabolites provide a much more sensitive method than EROD (CYP1A) or GST activity to monitor recent exposure to PAHs in dab.
- [show abstract] [hide abstract]
ABSTRACT: An h.p.l.c.-fluorescence technique was used to estimate relative concentrations of metabolites of xenobiotics in bile of 103 English sole (Parophrys vetulus) from both polluted and minimally polluted (reference) sites in Puget Sound, WA. Fish from polluted sites had concentrations of xenobiotics in bile with naphthalene-, phenanthrene- and benzo[a]pyrene-like fluorescence that averaged 9, 14 and 19 times, respectively, those of fish from reference sites. Within a polluted site, fish with liver lesions had significantly higher bile concentrations of xenobiotics with benzo[a]pyrene-like fluorescence than did fish without liver lesions. Individual metabolites of fluorene, phenanthrene, anthracene, biphenyl and dimethylnaphthalene were determined by g.l.c.-mass spectrometry in extracts of hydrolysed bile of three English sole from polluted waterways; concentrations ranged from 90 to 19000 ng/g, wet wt. Other xenobiotics were tentatively identified, but not quantified.Xenobiotica 09/1984; 14(8):633-46. · 1.98 Impact Factor
- Journal of Biological Chemistry 12/1974; 249(22):7130-9. · 4.65 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Female plaice (Pleuronectes platessa) were orally dosed with a gelatin capsule containing a solution of the technical PCB mixture Clophen A40 in sunflower oil. They were compared to plaice injected with a gelatin capsule containing only the sunflower oil at 10 and 16 days after injection. Even at 16 days after injection, the increase in concentrations of individual CB congeners in muscle was proportional to their contribution in Clophen A40. Biochemical effects are related to increases in concentrations of well-separable CB congeners in muscle, which increased by factors between 1.6 and 64 compared to the reference group of fish. Of both sampling points, total cytochrome P-450 levels were higher than the control groups, but surprisingly ethoxyresorufin-O-deethylase (EROD) activities did not differ between the groups. Enzyme-linked immunosorbent assay (ELISA) showed increased concentrations of the inducible cytochrome P-450IA1 in PCB-treated fish. The apparent lack of EROD induction may be due to competitive substrate inhibition by certain CB congeners present in the sample. The activity of glutathione-S-transferase (GST) (with CDNB as model substrate) was significantly elevated by PCB-treatment at day 16, but not at day 10. A longer time interval between injection with PCBs and induction of GST compared to P-450 monooxygenase activities has been reported earlier and may indicate that in fish both groups of enzymes are regulated individually and not as an [Arylhydrocarbon] gene battery as appears to be the case in mammals. Haemoglobin concentrations and MCHC were decreased in fish treated with Clophen A40. Haematocrit values did not differ between groups of fish.Science of The Total Environment 05/1992; 114:113-33. · 3.26 Impact Factor