Metabolism of drugs by the kidney

Abstract

Recent studies show that the kidney metabolizes a variety of drugs and chemicals. Renal enzymes catalyze oxidative, reductive, hydrolytic, and synthetic or conjugative reactions. The most important oxidative reactions are catalyzed by the cytochrome P-450-dependent mixed-function oxidase system; these consist of aromatic and aliphatic hydroxylations, N-, O- and S-dealkylations, and epoxidation. Reductive reactions, such as the conversion of aldehydes and ketones to alcohols, are well known to occur in renal tissue. The hydrolysis of esters and amides is also catalyzed by renal enzymes, and epoxide hydrase activity is present in the kidney. A variety of conjugates, such as glucuronides, sulfate esters, and glutathione conjugates, are formed by renal enzymes. Recent studies, in which the contribution of renal metabolism to the total conjugative metabolism of phenols has been quantified, show that the kidney makes a significant contribution to total metabolite production.