The effect of high protein diets on the kidneys of rats.

Abstract

As a part of a series of experiments designed to study the etiology of chronic nephritis, a number of rats were placed on diets made up of pure food materials, pure salts and vitamins. Diet A contained 20 per cent casein by weight, and was used as the standard or base diet. Diet B contained 76 per cent casein. Diet C contained 76 per cent casein plus the calculated amount of sodium bicarbonate necessary to neutralize the phosphorus and the sulphur derived from the casein. Diet D contained by weight, 20 per cent casein and 56 per cent purified egg albumen.

The rats, all of which came from the same stock, were, at the beginning of the experiment, from 50 to 300 grams in weight. They were kept on the various diets for 8 to 14 months.

Those on standard diet consumed 0.97 grams protein per 100 grams rat body weight per day. Those on Diets B and C ate 3.65 grams protein per 100 grams rat per day; those on high egg albumen Diet D, 3.60 grams. Figured in calories, the standard series ate 21.4 calories per 100 grams body weight per day; the high protein series, 21.2 calories; and the high egg albumen, 20.8 calories.

All the rats grew normally. The growth curves on the various diets were simillar and agreed with the standard curves of other observers. Young rats grew rapidly and maintained their growth well on all diets.

At various intervals the urine was tested for albumen, the sediment was examined, and quantitative nitrogen determinations were made. Traces of albumen were found in the urine of all our rats, in this and in other series as well. In but one instance did the albumen increase during the progress of the experiment, and that was in a rat which died of a chronic lung disease.