THE RELATIONSHIP OF DIETARY FACTORS TO RAT SERUM ALKALINE PHOSPHATASE

Weanling rats were fed dietary concentrations of 0%, 5%, 10%, 30%, and 91% casein. Complete absence of dietary protein resulted in death of the young animals within five weeks. Activity of serum alkaline phosphatase was at starvation levels during this period. Optimal growth was obtained at 30% dietary level of casein, and alkaline phosphatase activity was in the normal range. No effect on the enzyme could be attributed to the protein. There is a highly significant correlation between daily food consumption and serum phosphatase activity, which is attributed to the fat component of the various diets. Adult male rats were subjected to a three-week period of protein depletion, which was followed by a two-week period of protein repletion. The protein was supplied in the following forms: casein, dried brewer’s yeast, wheat gluten, casein plus wheat gluten, and dried brewer’s yeast plus gluten. Enzyme values at the end of the experiment were typical for the high fat diet (26%) which these animals were receiving. Once more there is a significant correlation between serum alkaline phosphatase activity and daily consumption of fat, whereas the protein component of the diet is without effect on the enzyme.