[Effect of heparin on incorporation of H3-thymidine in cells of transplantable line A-1].

The effect of heparin on the thymidine-3H incorporation into the cells of the continous line A-1 was studied. Cell incubation in medium 199 containing heparin (1--200 units per ml) did not lead to reduction of the labeled nuclei percentage; the duration of the G2 and S periods also failed to change in comparison with control. However, the incorporation intensity of thymidine-3H (the mean number of granules per one labeled nucleus) was decreased significantly. The data obtained indicated that heparin influenced the plasmalemma permeability, but had no effect on the DNA synthesis. The antimitotic action of heparin was apparently due to its influence on the cell surface.