TY - JOUR T1 - THE EFFECT OF PHENOBARBITAL PRETREATMENT ON THE BIOTRANSFORMATION OF <sup>3</sup>H-DIGITOXIGENIN TO 6β-HYDROXY-3-EPIDIGITOXIGENIN BY RABBIT LIVER HOMOGENATES JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 361 LP - 364 VL - 2 IS - 4 AU - W. H. BULGER AU - S. J. STOHS Y1 - 1974/07/01 UR - http://dmd.aspetjournals.org/content/2/4/361.abstract N2 - 3H-Digitoxigenin was incubated over a time course of 15, 30, 45, and 60 min with liver homogenates prepared from phenobarbital-pretreated and control male rabbits. Pretreatment with phenobarbital preferentially enhanced the formation of 6β-hydroxy-3-epidigitoxigenin at all time points and significantly decreased the accumulation of 3-epidigitoxigenin at 45 and 60 min. The formation of 5β-hydroxydigitoxigenin was significantly greater at 15, 30, and 45 min in the phenobarbital group. Digitoxigenin disappeared at approximately the same rate from incubation flasks containing liver homogenates of phenobarbital-treated and control rabbits. Phenobarbital pretreatment had no influence on the formation of 3-ketodigitoxigenin (3-dehydrodigitoxigenin). Aniline hydroxylation, cytochrome P-450 content of liver microsomes, and liver weight were elevated in the phenobarbital-pretreated rabbits as compared to the controls. The milligrams of hepatic microsomal protein per g of liver were not significantly different between the two groups of animals. Copyright © 1974 by The American Society for Pharmacology and Experimental Therapeutics ER -