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

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 24 h. No significant change occurred in levels of radioactivity from 24 to 168 h. 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 (less than 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).