Converting enzyme inhibition prevents postprandial hyperfiltration in rats with renal mass ablation

Food restriction or chronic converting enzyme inhibition (CEI) both limit age-related glomerulosclerosis and the associated proteinuria which occurs spontaneously in rats with renal mass ablation. Since hyperfiltration consecutive to the decreased number of nephrons may be damaging to the kidney, we investigated how fasting and CEI compare in lowering glomerular filtration rate in partially nephrectomized rats. Male Wistar rats were subjected to 3/4 nephrectomy and chronically catheterized. A week after surgery, the animals were separated into two groups, one control and one treated with the converting enzyme inhibitor perindopril (1 mg/kg/24 h) for ten days. In the control untreated 3/4 nephrectomized rats, successive measurements of kidney function in the same animal showed that renal blood flow and glomerular filtration were 30 to 50% higher in fed than in fasted animals. In the group treated with perindopril, there was no longer any such difference in the renal blood flow and filtration rate. These results indicate that, by blunting postprandial hyperfiltration, chronic converting enzyme inhibition is as effective as food restriction in reducing the load delivered to the kidney.