The metabolism of biphenyl by isolated viable rat hepatocytes.

1. The metabolism of biphenyl by isolated viable rat hepatocytes has been studied and a tentative scheme of metabolism proposed which involves initial hydroxylation at the 2- and 4-positions followed by conjugation and/or further hydroxylation of these primary metabolites. 2. Biphenyl was toxic to viable hepatocytes when used at a concentration approaching that used in conventional microsomal assay systems. 3. The production of small amounts of 4-hydroxybiphenyl appears to activate its subsequent conjugation. 4. The data presented in this paper integrate previous results obtained with cell fractions, and demonstrates the importance of the isolated, viable hepatocyte system as a model for total drug metabolism.