Analgesic-induced renal papillary necrosis in the Gunn rat: the comparative nephrotoxicity of aspirin and phenacetin.

Homozygous Gunn rats, mutant Wistars genetically lacking glucuronyl transferase, develop renal papillary necrosis after single oral doses of aspirin and of phenacetin. The lesion appears significantly more frequently with aspirin than phenacetin, and at lower doses. The model is a convenient one with which to study analgesic nephrotoxicity.