Effect of different levels of vitamin B6 in the diet of rats on the content of pyridoxamine-5'-phosphate and pyridoxal-5'-phosphate in the liver.

The pyridoxal-5'-phosphate (PLP) and pyridoxamine-5'-phosphate (PMP) contents were determined in livers of rats fed diets containing different levels of vitamin B6 (0.3-22.9 ppm). Maximum growth was attained at vitamin B6 intake levels of greater than or equal to 24 micrograms/day. Maximum PLP and PMP levels in a crude liver homogenate were reached at intake levels of 75 and 9 micrograms/day respectively. In the 100 000 g supernatant fraction of liver the maximum PLP level was reached at intake levels of greater than or equal to 37 micrograms/day. The PLP/PMP-ratio of the crude liver homogenate increased from 0.6 up to values of appr. 1.5 at the higher intake levels. The PLP/PMP-ratio in the 100 000 g supernatant was more variable and did not show a consistent trend at varying vitamin B6 intakes.