The effect of food ingestion on intestinal and serum alkaline phosphatase in rats.

A study has been made of the effect of the ingestion of various foods on the concentration of alkaline phosphatase in the intestinal mucosa and the blood serum in rats. We have confirmed the findings of other investigators that fasting will reduce the serum alkaline phosphatase in rats (l-5) and that the feeding of fat or of protein but not of carbohydrate will increase it (2, 5). We have also found that the alkaline phosphatase of the intestinal mucosa reacts to the ingestion of various foods in the same way as that of the serum. In addition, we have found that the alkaline phosphatase of both intestinal mucosa and serum is increased by food even when bile is excluded from the intestinal tract. Flock and Bollman (6) demonstrated that the alkaline phosphatase of intestinal lymph was low in the fasting rat and increased after either a fatfree meal or the same meal with added fat. The plasma alkaline phosphatase decreased to very low levels when the intestinal lymph was drained off continuously. They concluded that the largest part of the plasma alkaline phosphatase in the rat is intestinal in origin and reaches the plasma via the lymph. In a later paper (7) they found that the bile was concerned in the “transport and release” of the intestinal phosphatase. Little work has been done on the effect of foods on the actual concentration of phosphatase in the intestinal mucosa. Bellini and Cera (8) found that it was increased during absorption of neutral fats. Lawrie and Yudkin (9) found that it was lower in fasting’ rats that had been maintained on a high carbohydrate diet than in the rats that had been maintained on a high fat or high protein diet.