Synthetic diets were fed to adult rats for four weeks to determine the effects of dietary stearic acid, oleic acid, glycerol, Crisco, and vitamins, A, D, and E on the activity of serum alkaline phosphatase and serum tributyrinase. On a diet devoid of fats or fatty acids, the rats manifested abnormally low enzyme levels, which for serum alkaline phosphatase fell to values characteristic of starvation. Basal levels of the two enzymes, obtained with a fat free diet, were not altered by the ingestion of glycerol or vitamins A, D, and E. Dietary stearic acid, oleic acid, and Crisco, each significantly increased activity of phosphatase and tributyrinase and it would appear that both enzymes are concerned with intestinal absorption of fatty acids. The effect of oleic acid was most pronounced with both enzymes. The rats all gained weight during the tests so none of the variations in enzyme levels can be attributed to inanition. After the dietary test periods, all groups were starved for one week. Serum phosphatase values fell to the same constant low levels for all animals. Tributyrinase values rose towards levels which suggest that the enzyme is concerned with mobilization of depot fats during periods of fasting.
Identification of Rat Serum Alkaline Phosphatase Isoenzyme by means of Wheat Germ Agglutinin.