Formation of ortho-phenylphenol glutathione conjugates in the rat liver.
1. The radioactive materials(s) derived from 14C-ortho-phenylphenol (OPP) became bound irreversibly to hepatic microsomal macromolecules in an NADPH-generating system, and the binding was inhibited by cysteine and glutathione (GSH). 2. A water-soluble phenyl-hydroquinol (PHQ)-GSH conjugate was produced by non-enzymic reaction between phenyl-p-benzoquinone and GSH in alcoholic aqueous solution, and the structure of the conjugate was confirmed by its 13C-n.m.r. spectrum. 3. When 14C-OPP and GSH were incubated in a microsomal NADPH-generating system, radioactive material derived from the aqueous phase of the incubation mixture was similar to the synthetic PHQ-GSH on t.l.c. 4. PHQ-GSH was excreted as a minor conjugate into the bile after oral administration of OPP (1000 mg/kg) to rats, the cumulative biliary excretion of the conjugate was about 4% of the dose in 6 h.