Abstract
Uptake of pyridoxine by ascites-sarcoma cells in vitro has been investigated. Pyridoxine was uptaken against concentration gradient at low initial concentrations of pyridoxine and accumulated in the cells as phosphorylated forms of B_6. The uptake of pyridoxine by ascites-cells was greatly enhanced in the presence of glucose but it was diminished by the addition of either 2,4-dinitrophenol or sodium fluoride with glucose. 4-Deoxypyridoxine also inhibited the uptake of pyridoxine in the cells. Incubation of ascites-cells with glucose and labelled pyridoxine resulted in accumulation of labelled pyridoxine in the cells. Similarly, the accumulation was decreased by the addition of each 2,4-dinitrophenol or sodium fluoride. Furthermore, in the presence of vitamin B_6 phosphates and 4-deoxypyridoxine, labelled pyridoxine uptake was inhibited. These results support the conclusion that pyridoxine was uptaken in ascites-sarcoma cells by an energy-associated process.
