Studies Alkaline Phosphatase during Development Part II: Changes in alkaline phosphatase activity and isozyme patterns in the serum of healthy children and of children with various diseases

Abstract

SummaryIn order to clarify the organ origins of high serum alkaline phosphatase in children during development and in children with various diseases, the serum alkaline phosphatase activity and isozyme patterns of children, umbilical cord blood and pregnant woman were investigated by the agar gel electrophoresis and heat stability test. In two infant autopsy cases, isozyme patterns were also investigated in several organs.1) Serum alkaline phosphatase activity of children was about 2.5 to 3 times as high as that of adults. In the group below 1 year of age and the group between 11 and 15 years of age, the levels were higher than in other groups.2) Alkaline phosphatase isozyme pattern in normal serum was showed as a single band (band III) around the α2‐globulin fraction in all groups.3) The alkaline phosphatase isozyme patterns in normal serum were divided into a pattern with non‐shifting peak after heat treatment at 56°c for 10 minutes and another with shifting peak to α1‐globulin side. In younger groups, the pattern with non‐shifting peak was more frequently seen and with growing the pattern with shifting peak increased. In adults, the peak shifted in all cases after heat treatment.4) The decreasing rate of alkaline phosphatase activity of normal serum by heat treatment was within the range of about 70–80% in each age group without remarkable differences. No calculation was possible in adult group, because the activity was markedly low.5) Serum alkaline phosphatase activity of pregnant women showed slightly higher than umbilical cord blood, about 3 times higher than in normal adults.The isozyme patterns were different between sera of pregnant women and umbilical cord blood.The decreasing rate of alkaline phosphatase activity after heat treatment (56°c for 10 minutes) was less in serum of pregnant women than in other sera, showing greater heat stability.6) Serum alkaline phosphatase was always high in diseases of liver and bone.Five bands of alkaline phosphatase activity were noted in the sera of normal subjects, pregnant women and children with various diseases.In liver diseases without marked obstruction and in bone diseases, the alkaline phosphatase isozyme pattern appeared in α2‐globulin band (band III). In liver diseases with marked obstruction, α1‐globulin band (band II originated from the liver) and β‐globulin band (band V probably from intestine) appeared. In one case, an Albumin‐α1 globulin band (band I) appeared.7) The alkaline phosphatase isozyme patterns in liver, bone, small intestine and kidney showed different electrophoretic migration rates indicating organ specificity.8) To sum up, serum alkaline phosphatase of the healthy children appeared to be originated from liver and bone. During childhood the alkaline phosphatase predominantly consists of bone origin, while in adults, major activity appeared to be hepatic origin.