On the urinary excretion of 4-pyridoxic acid and its significance.

That most of the vitamin B6 taken in the body is excreted in the urine as 4-pyridoxic acid (PIC), has been reported by Huff (1), Sarett (2), Butler (3) and MƒÓller (4), and its simple method of estimation has been discussed from various angles. It has also been found that of the three forms of vitamin B6, PIC excretion from pyridoxal (PAL) is most rapid and large in amount, possibly due to the structural composition. In the present work PIC excre tion was estimated based on an existing fluorometric method and from the results obtained in respect to the excretory states in various diseases and from the results after vitamin B6 loading, the significance of its excretion was in vestigated.