THE TRANSPORT OF ¹⁴C-LABELED NITROGEN MUSTARD N-OXIDE THROUGH CELLULAR MEMBRANE TREATED WITH TWEEN 80 IN VITRO

Abstract

The increased sensitivity of rat ascites hepatoma cells to nitrogen mustard N-oxide (HN₂-O) by treatment with Tween 80 in vitro was analyzed with ¹⁴C-labeled nitrogen mustard N-oxide (¹⁴C-HN₂O). The transport of ¹⁴C-HN₂O into the parts of cells was studied; whole cells, the fraction precipitated with trichloroacetic acid from the water-soluble cellular protein, and the total of precipitated fraction and water-insoluble fraction in the cells were examined. In the whole cell and fraction the transport was increased by pretreatment with Tween 80. The binding ratio of ¹⁴C-HN₂-O to the cellular homogenate was not altered by the pretreatment.
These results suggest the increased transport of ¹⁴C-HN₂-O into the tumor cells by treatment with Tween 80 which made the cellulr membrane thinner. The significant part of the differences in natural sensitivity of rat ascites hepatomas to HN₂-O seems to depend partially on the different cellular permeability of the drug.