The effect of protein intake on the lifelong changes in renal function of rats with a solitary kidney damaged at young age.

Changes in renal function were followed lifelong in male rats with only 1 kidney either intact or damaged by ureteral obstruction or ischemia. After surgery the rats were given a low (12%) or a high (36%) protein diet. After a period with a stable glomerular filtration rate, which was longer on the low protein diet, there was a linear decline in rats with an intact single kidney. The rate of decline was highest on the high protein diet, resulting in a shorter survival time. A decrease in urine osmolality and an increase in protein excretion preceded the decrease in filtration rate, while it was followed by an increase in blood pressure. The glomerular filtration rate of the rats with a single damaged kidney initially recovered to 75 to 80% of that of rats with an intact single kidney on the same diet. There was a linear decrease in the glomerular filtration rate, with the highest rate of decrease on the high protein diet. The mean survival time was less than that of rats with a single intact kidney. Proteinuria preceded the decrease in filtration rate, while hypertension was observed later. We conclude that in rats with a solitary kidney renal failure eventually develops. A low protein diet postpones and attenuates this development but it does not prevent it.