Abstract
In the cross-resistance studies in vitro and in vivo, three sublines of Yoshida sarcoma with high resistance to nitrogen mustard (HN2) were highly susceptible to improsulfan, and there was no significant difference in the extent of improsulfan uptake and its binding to desoxyribonucleic acid between the original and HN2-resistant cells. The results obtained by the transport study of improsulfan at a dose range of 0.01 to 1 mM suggest that improsulfan uptake is non-active by Yoshida sarcoma cells. The factors of resistance to HN2 demonstrated in these resistant cells may not serve as factors of resistance to improsulfan.
