Abstract
In an attempt to further characterize and compare the drug-metabolizing potential of lung and liver, the subcellular localization and activities of several transferases were determined in rabbits using one or more substrates. Microsomal fractions were found to contain UDP-glucuronyltransferase activity, whereas the supernatant fractions contained N-acetyltransferase, glutathione S-aryltransferase, and phenol sulfotransferase. With one exception, the enzyme activity in lung was considerably less than the activity toward the same substrate in liver, and in several instances no activity was detected in lung. The activity of N-acetyltransferase toward the substrate p-aminobenzoic acid was equal in lung and liver. Hepatic N-acetyltransferase activity toward sulfadiazine was only about 15% that toward p-aminobenzoic acid in liver and was barely detectable in lung. UDP-glucuronyltransferase activity toward both p-nitrophenol and phenol-phthalein was undetectable in lung. Similarly, phenol sulfotransferase activity was not demonstrable in lung. Four-day phenobarbital pretreatment produced increases in cytochrome P-450 and NADPH-cytochrome c reductase in liver but no increase in any of the transferases in either organ. Pretreatment with 3-methylcholanthrene or SKF 525-A had no effect on any of the transferases studied.
Footnotes
- Received January 10, 1974.
- Copyright © 1974 by The American Society for Pharmacology and Experimental Therapeutics