TY - JOUR T1 - THE FORMATION OF COMPLEXES ABSORBING AT 455 NM FROM CYTOCHROME P-450 AND METABOLITES OF COMPOUNDS RELATED TO SKF 525-A JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 386 LP - 390 VL - 2 IS - 4 AU - MILDRED K. BUENING AU - MICHAEL R. FRANKLIN Y1 - 1974/07/01 UR - http://dmd.aspetjournals.org/content/2/4/386.abstract N2 - A number of compounds with structural similarities to SKF 525-A (adiphenine, benactyzine, propoxyphene, diphenhydramine, desipramine, and nortriptyline) are capable of forming metabolite-cytochome P-450 complexes absorbing maximally at 455 nm when metabolized by rat hepatic microsomes. The optimum substrate concentrations for the maximum rate of formation of 455-nm complexes in microsomes from untreated rats and from rats pretreated with phenobarbital were between 25-50 µM. With microsomes from phenobarbital-induced rats, the maximum rate of formation of 455-nm complexes was proportional to the concentration of induced cytochrome P-450. The rate of formation of 455-nm complexes was highest with microsomes from phenobarbital-induced animals, intermediate with microsomes from untreated rats, and lowest with microsomes from 3-methylcholanthrene-inducd rats. Copyright © 1974 by The American Society for Pharmacology and Experimental Therapeutics ER -