MAJOR DIFFERENCES IN THE EXTENT OF CONJUGATION WITH GLUCURONIC-ACID AND SULFATE IN HUMAN PERIPHERAL LUNG

Short-term organ cultures of human peripheral lung metabolise benzo(α)pyrene to water-soluble metabolites. Enzymic hydrolysis of these water-soluble metabolites with arylsurphatase (with saccharic acid 1,4-lactone) but not with β-glucuronidase released significant amounts of ethyl acetate-soluble radioactivity, which co-chromatographed with metabolites of benzo(α)pyrene. Similar studies of human peripheral lung showed that 1-naphthol, a model phenolic substrate, was metabolised extensively to its sulphate conjugate with little or no glucuronic acid conjugate being formed. In marked contrast to this, with short-term organ culture of rat lung, 1-naphthol is mainly conjugated with UDP-glucuronic acid. Thus, in human but not in rat lung, phenolic substrates such as monohydroxybenzo(α)pyrenes or 1-naphthol are metabolised predominantly to their respective sulphate conjugates with little or no glucuronide conjugates being formed. © 1979.