DIFFERENTIAL EFFECT OF XANTHOPTERIN AND BIOPTERIN ON CELL-GROWTH

1. Xanthopterin inhibited proliferation of primary renal proximal tubu le cells (RPTC) and LLC-PK1, cells while in a growth phase but when in cubated at confluence the cells were relatively insensitive. 2. The gr owth of malignant human prostate PC-3 cells was also inhibited by xant hopterin in a concentration and time dependent manner. 3. Dunning R332 7 AT-3 rat prostate tumor cells which were exposed to xanthopterin in vitro before their in vivo inoculation resulted in smaller tumours whi le in vivo administration of xanthopterin following implantation also resulted in smaller tumors. 4. Xanthopterin exerts differential effect s on cell growth dependent upon the cell origin and their state of pro liferation.