Inhibition of serum alkaline phosphatase activity by phenylalanine and cholic acid.

Serum alkaline phosphatase activity was found to increase more markedly in patients with liver cirrhosis than in patients with peptic ulcer and this increase was found to be influenced by blood types. After testing several amino acids and bile acids, phenylalanine and cholic acid were chosen and their inhibitory effects upon serum alkaline phosphatase activity were studied in 66 patients with various liver diseases. It was found that the combination of both agents demonstrates different patterns of inhibition between the patients with liver cirrhosis and obstructive jaundice. This inhibitory effects were also variable among cases of different blood types. Basing upon the present observation, the possible source of the elevated alkaline phosphatase activity in liver cirrhosis was discussed.