Abstract
Ehrlich ascites tumor-bearing mice were treated with colchi-cine or mitomycin C. Under colchicine, adenylate cyclase activity in tumor cells decreased to about a third of the untreated control level, whereas 5'-nucleotidase activity increased to almost twice the control level. Colchicine treatment resulted in about a 30 % reduction of 3H-thymidine incorporation into DNA. Mitomycin C inhibited the incorporation of 3H-thymidine much more mark-edly but changes in the two enzyme activities were less than under colchicine. The two enzyme activities and 3H-thymidine incorporation into DNA showed parallel changes with lapse of time after inoculation of tumor cells into mice. Thus, the colchicine effects on the two enzyme activities seemed not due simply to inhibition of cell proliferation. The two enzymes seemed to be associated differently with the microtubular system in Ehrlich ascites tumor cells.
