The influence of abo blood groups, secretor status and fat ingestion on serum alkaline phosphatase

Abstract

Two experiments have been performed in an attempt to clarify the relationship between liver and intestine alkaline phosphatase iso-enzymes and ABO blood group and secretor phenotype. In the first experiment 6 subjects, each of phenotype O secretor, O non-secretor, A secretor and A non-secretor, were studied on two occasions. On the first occasion a fasting sample was followed by ingestion of a non-fat meal, and blood was taken 2 and 4 h thereafter. A similar procedure was followed on the second occasion except that a fatty meal was ingested. The serum samples had determinations performed of total alkaline phosphatase activity and percentage inhibition thereof by l-phenylalanine which gives a measure of the intestinal contribution. The sera were also all subjected to starch gel electrophoresis. A second intestinal electrophoretic band was found in all sera from O secretors and in none of the sera from the other 3 phenotypes. Males had significantly higher mean fasting alkaline phosphatase levels than females. There was a significant increase in total alkaline phosphatase activity 4 h after a fatty meal in O secretors, as compared with a non-fat meal. O secretor subjects had significantly higher values for percentage inhibition of alkaline phosphatase activity by l-phenylalanine than did the other 3 phenotypes, indicating a larger intestinal contribution to total serum alkaline phosphatase activity. The percentage l-phenylalanine inhibition did not change after either non-fatty or after fatty food. In order to assess the last point a second experiment was performed on a further 12 O secretor subjects. Blood was drawn fasting and 7 sol1 2 h following a synthetic fat meal. Total serum alkaline phosphatase, percentage l-phenylalanine inhibition and percentage urea inhibition (which gives a measure of liver and bone iso-enzyme contributions to total activity) were determined. A considerable variation was observed between individual O secretors, the effect of fat in elevating total serum alkaline phosphatase being much more marked in some individuals than in others. The results again indicated that the proportional contribution of the intestinal iso-enzyme remained constant. This last observation suggests that the mechanism of release of alkaline phosphatase iso-enzymes from parenchymal cell into serum is influenced in a similar manner in both liver and intestine by the O and secretor genes.