METABOLIC EFFECTS OF DIETARY PROTEIN LEVEL WITH CALORIC RESTRICTION IN COLD-EXPOSED RATS

Male albino rats were fed isocaloric diets (5%, 20%, and 40% protein and 10% corn oil by weight) in restricted amounts (6 g/rat per day) at environmental temperatures of 22 °C and 2 °C. Measurements were made of urinary excretion of nitrogen, potassium, sodium, phosphorus, and creatinine, of blood levels of glucose, urea, amino nitrogen, packed cell volume, and serum total proteins and of body contents of protein, moisture, and total crude fatty acids. Metabolic effects of food restriction were readily apparent at 22 °C and the diet appeared to play a role in modifying some of these effects in approximate proportion to the dietary protein level. With superimposition of cold exposure, metabolic differences among groups were decreased in degree with some suggestive evidence of a beneficial effect of increased dietary protein level and of a deleterious effect of decreased dietary protein (high carbohydrate) under these conditions.