N-phenyl anthranilic acid: an agent for inducing and studying renal papillary necrosis in the rat.

The oral administration of N-phenyl anthranilic acid (N-PAA) to rats causes a lesion of the renal papillary tip which closely resembles that seen after dosage with anti-inflammatory drugs. Functional and histological changes which take place throughout the progression of the lesion have been studied. After sloughing of the necrotic papillary tip healing takes place with a return to normal function. The lining epithelium of the new, truncated apex is hyperplastic; hyperplasia of the renal pelvic epithelium opposite the necrotic area has been noted after giving anti-inflammatory drugs to animals and also occurs in patients with renal papillary necrosis.