Arachidonic acid is metabolized to prostaglandin, lipoxygenase products, and products of the microsomal cytochrome P-450 enzymes of the kidney. The distribution of the metabolizing enzymes and their regulation and pharmacologic manipulation are reviewed. The mechanisms of release of arachidonic acid from membrane lipids through a surface-mediated receptor mechanism are also discussed. The localization of the various enzymes and product formation may have profound effects on glomerular filtration, renal blood flow, and electrolyte excretion. Therefore, an understanding of the potential sites of inhibition of the nonsteroidal anti-inflammatory drugs is important in assessing their effects on renal function.