Effect of protein intake on renal function and structure in partially nephrectomized rats.

To examine the effect of high protein intake on renal function and structure in rats with 5/6 nephrectomy chronic renal failure, we pairfed rats with chronic renal failure and sham-operated control rats diets of 14 or 37% protein content for up to 6 months. High protein intake accelerated mortality in rats with chronic renal failure and resulted in a more rapid rate of decrease in renal function as established by plotting the reciprocal of plasma creatinine versus time. High protein intake also increased urine protein excretion in experimental and control rats. High protein intake was associated with increased tubular dilatation and interstitial inflammation, both of which were striking features in rats with chronic renal failure. Glomerular sclerosis was prominent in rats with chronic renal failure. These rats had smaller glomerular tuft dimensions than control rats irrespective of their protein intake. We conclude that high protein intake accelerates the course of chronic renal failure in rats. The pathologic process involves glomerular sclerosis; however, interstitial inflammation and renal tubular changes leading to cyst formation also appear to influence the process adversely.