STIMULATION OF DRUG OXIDATION IN KIDNEY MICROSOMES BY PHENOBARBITAL

Pretreatment of rats and rabbits with Phenobarbital (80 mg/kg and 60 mg/kg respectively) caused a 30% increase in the liver weight relative to body weight. There was a smaller increase in the kidney weight (7% in rats and 10% in rabbits) which was not statistically significant. The yields of microsomes per gram of liver was also increased by about 90% and 60% in rats and rabbits respectively, but only a slight increase was observed for kidneys (12% and 18% respectively). Pretreatment with Phenobarbital, 3,4-Benzpyrene or Chlorophenothane neither significantly increased the cytochromes of rat kidney microsomes, nor the oxidative drug metabolism. However, in the kidneys of rabbits the cytochrome-b5-and P450-concentrations and drug metbolism were 2-3 fold higher after Phenobarbital. The correlation between P450 content and drug oxidase activity in the kidney microsomes of untreated and Phenobarbital treated rabbits was low. Suspensions of rabbit kidney microsomes revealed the same spectral changes after addition of Hexobarbital or Aniline as those reported for liver microsomes. © 1968 Springer-Verlag.