The source and clinical significance of alkaline phosphatases in liver diseases.
The authors studied total serum alkaline phosphatase (E.C. 3.1.3.1) activity and its isoenzyme spectrum 1) in relation to the activity of liver diseases, 2) in relation to cholestatic and non-cholestatic liver diseases. The isodistribution of the alkaline phosphatase isoenzymes (the bone, liver and intestinal fraction) in the serum was studied by the heat inactivation and inhibition method and by electrophoretic separation on agar gel. The results showed that alkaline phosphatase had a close diagnostic bearing not only on cholestatic forms of hepatobiliary diseases, but also on the activity of liver disease. The main source of elevated serum alkaline phosphatase activity in the serum of patients with hepatobiliary diseases is the liver isoenzyme. In the serum alkaline phosphatase isoenzymogram, an abnormally large proportion of this isoenzyme is found more frequently than elevation of total alkaline phosphatase activity.