@article {Okita147, author = {R T Okita and B S Masters}, title = {Effect of phenobarbital treatment and cytochrome P-450 inhibitors on the laurate omega- and (omega - 1)-hydroxylase activities of rat liver microsomes.}, volume = {8}, number = {3}, pages = {147--151}, year = {1980}, doi = {10.1124/dmd.8.3.147}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {The omega- and (omega - 1)-hydroxylase activities for lauric acid were investigated in rat liver microsomes. Treatment of rats with phenobarbital selectively induced the hydroxylation of the fatty acid (omega - 1)-hydroxylase activity two- to threefold, but had little effect on the omega-hydroxylation reaction. SKF 525-A, metyrapone, and alpha-naphthoflavone inhibited (omega - 1)-hydroxylation, but had only neglible effects on omega-hydroxylation. Metyrapone at 10(-4) inhibited the specific activity of (omega - 1)-hydroxylase 70\% in phenobarbital-pretreated rats, but produced only a 10\% inhibition of the omega-hydroxylation activity. alpha-Naphthoflavone at 10(-4)M inhibited (omega - 1)-hydroxylase activity 60\% in untreated and beta-haphthoflavone-pretreated rats, while omega-hydroxylase activity was decreased only 20\%. A selective effect was also observed when microsomes were stored overnight at 4 degrees C. Declines of 50\% and 70\% were observed in the (omega - 1)-hydroxylase activities after 24 and 48 hr, respectively, whereas omega-hydroxylation decreased only 10-20\%. The differential effects on omega- and (omega - 1)-hydroxylase activities of a variety of conditions suggest that distinct cytochromes P-450 mediate the two fattty acid hydroxylases in liver microsomes.}, issn = {0090-9556}, URL = {https://dmd.aspetjournals.org/content/8/3/147}, eprint = {https://dmd.aspetjournals.org/content/8/3/147.full.pdf}, journal = {Drug Metabolism and Disposition} }