Renal hypertrophy and function in irradiated and nephrectomized rats fed a high protein diet

¹ U. S. Naval Radiological Defense Laboratory, San Francisco, California

Male rats exposed to a total of 740 rad X-irradiation were fed a high protein diet and unilaterally nephrectomized to investigate functional and compensatory regenerative capacity of the kidney as probable indices of residual radiation injury. The extent of compensatory hypertrophy after nephrectomy showed a significantly greater increase due to the high protein diet but no effect due to irradiation. Estimates of maximal tubular excretions of p-aminohippurate (PAH), however, were significantly greater in irradiated groups than in control groups when determined 3 weeks postnephrectomy. Renal clearances of C_In and C_PAH were significantly depressed after nephrectomy but not after radiation. Histological studies of the kidneys did not indicate renal damage by radiation except for an isolated instance of a renal neoplasm in an irradiated, nephrectomized rat fed a high protein diet. The results indicate that radiation does not modify compensatory hypertrophy after unilateral nephrectomy but appears to increase the apparent functional capacity of the tubules.