End-stage renal disease is a common cause of death in dogs and cats. Unfortunately, despite appropriate therapy for the or cat with re- nal disease. First, the disease is inherently unstable and fre- quent reevaluations and adjustments in therapy are re- quired. Second, because of the tremendous cost and technical difficulty associated with therapy for end-stage uremia (i.e., dialytic therapy or renal transplantation), ef- forts designed to slow the rate of progression of renal dis- ease are particularly important in veterinary medicine.

The cause of progressive renal injury has been the focus of great attention in nephrology. It has long been recog- nized that renal disease in human beings usually progress- es, even if appropriate therapy eradicates the primary cause of the renal injury. Thus, once renal injury reaches a cer- tain threshold, secondary factors appear to be the critical determinants of progressive renal injury.