Metabolism and subsequent covalent binding of benzo[a]pyrene to macromolecules in gonads and liver of ripe English sole (Parophrys vetulus)

Abstract

1. Ripe English sole (Parophrys vetulus) force-fed [³H]benzo[a]pyrene, contained 1% of the dose in liver, 0.2% in ovary and 0.1% in testis, after 24h. No significant change occurred in levels of radioactivity from 24 to 168h.

2. Gonads and blood contained substantially larger proportions of unchanged benzo[a]pyrene (15–37% of tissue radioactivity) and organic solvent-soluble metabolites (6–35%) than did liver and bile.

3. T.l.c. revealed the presence of phenols, quinones, 7,8-dihydro-7,8-dihydroxy- and 9,10-dihydro-9,10-dihydroxy-benzo[a]pyrene in liver and gonads.

4. A small proportion (<10%) of the radioactivity in liver and gonads was present as glucuronides and sulphates; bile contained a higher proportion (ca. 20%) of total radioactivity as glucuronides and sulphates.

5. Benzo[a]pyrene intermediates were covalently bound to liver proteins and DNA, and to a lesser extent to gonadal proteins (male and female fish) and gonadal DNA (confirmed for testis only).