Compensatory renal growth after unilateral ureteral obstruction.

Compensatory renal growth after unilateral ureteral obstruction. The accumulation of bulk renal protein, RNA and DNA was studied in mice during a 35-day period of accelerated renal growth in the kidney contralateral to that obstructed by acute ureteral ligation. Control mice were sham-operated and nonoperated. RNA was determined by the method of Monroe and Fleck, DNA after Ceriotti and protein according to Lowry. The kidney contralateral to its acutely obstructed mate demonstrated accelerated growth with increases of 60% (protein), 52% (RNA) and 46% (DNA) at 35 days, These levels were significantly higher than the levels of protein (23%), RNA (24%) and DNA (23%) that were recorded in nonoperated animals. The rate of accelerated growth was similar to that previously reported after contralateral nephrectomy. Growth in the contralateral kidney occurred through both hypertrophy and hyperplasia with hypertrophy contributing most to the increase in size. In contrast, as observed in nonoperated mice, normal renal growth occurred through hyperplasia. The data suggest that the stimulus for accelerated renal growth is the functional rather than the physical removal of renal mass and that, once initiated, contralateral growth proceeds at a rate independent of the initial stimulus.