Intracellular Distribution of Vitamin B 6 in Rat and Mouse Livers and Induced Rat Liver Tumors. ∗

Abstract

Summary

The intracellular distribution of vitamin B₆ in rat liver tumors induced by 4-dimethylaminoazobenzene and in the livers of rats and mice before and after administration of the azo dye was determined after differential centrifugation of the tissue homogen-ates in hypertonic sucrose solution.

In all cases vitamin B₆ was concentrated in the washed large granules or mitochondria (28 to 45% of total) and in the supernatant fluids (45 to 64% of total). The washed nuclear fractions contained 3 to 11% of the total vitamin B₆ present. The unwashed small granules or microsomes contained 4 to 8% of the total vitamin B₆ in the case of normal rat liver one washing reduced the level to about 1 1/2%.

The ingestion of the azo dye reduced the levels of the vitamin in the large granule and supernatant fluid fractions of the livers in each species. The decrease in protein content of the large granules paralleled the decrease in vitamin B₆ content. The large granule and supernatant fluid fractions of the liver tumors contained even less vitamin B6 than was found in the corresponding fractions from the livers of rats fed the dye and the ratio of the vitamin to protein was also much lower.