Abstract
In an attempt to explain the discrepancy between the results reported by different investigators on the relation between dietary protein and renal lesions, Moise and Smith 1 have postulated that young rats may have greater powers of adaptation than old ones, and accordingly may be less susceptible to the injurious effect of an excessively high protein ration. This suggestion was based upon the observation of Arataki, 2 that the formation of glomeruli continues throughout the first hundred days of life, and upon the fact that a very large proportion of the published observations reporting absence of pathologic renal lesions were initiated on young rats. In studies (Moise and Smith 1 ) with adult rats fed adequate diets rich in protein, structural lesions were observed at intervals from 90 to 150 days after unilateral nephrectomy. These lesions included both glomerular and tubular changes. The former consisted in serum in the capsular spaces, proliferation of the epithelium of Bowman's capsule with and without adhesions between the tuft and capsule, fibrous thickening of Bowman's capsule, partial fibrosis of the glomerular tuft, and in many instances infiltration of round cells in and around these areas. The most striking tubular changes were dilatation and active proliferation of the lining epithelium. The experiments were initiated at ages between 121 and 202 days and completed at ages between 271 and 348 days.
In our further studies of a similar nature the right kidney was removed from a small series of rats at the age of 30 days. Immediately following the nephrectomy the animals were divided into two groups, placed on the “standard” diet (18 per cent casein) and high protein ration (85 per cent casein) respectively. At the present time specimens of the left kidney are available at time intervals after nephrectomy, varying from 177 to 384 days on the standard diet, and from 171 to 277 clays on the high protein food.
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