Excretion of 4-Pyridoxic Acid during Deoxypyridoxine and Pyridoxine Administration to Mongoloid and Non-Mongoloid Subjects

Abstract

The excretion of 4-pyridoxic acid (4PA) was studied in mongoloid subjects and controls of similar age and weight living in the same cottages and eating the same diet. The base-line excretion of 4PA was similar in the two groups. On the first day of deoxypyridoxine (DP) administration, a fourfold increase in 4PA excretion occurred in both groups; but on continued DP administration, 4PA excretion increased significantly less in mongoloid subjects compared with controls. On pyridoxine and DP administration loading, a significantly greater excretion of 4PA occurred in mongoloids compared with controls. The above data suggest that mongoloid subjects have a smaller dissociable pool of vitamin B₆ and that the enzymes of vitamin B₆ catabolism have greater activity in mongoloid subjects than in controls.