Deoxyuridine Suppression Test On Isolated Rat Bone-marrow Cells and the In-vitro Effect of Bidisomide

The deoxyuridine suppression test was performed on isolated rat bone marrow cells in order to study the effect of bidisomide, a new Class I antiarrhythmic agent, on folate-dependent DNA synthesis. Methotrexate and 5-fluorouracil, two known inhibitors of DNA synthesis, were included in the study to validate the test system. Methotrexate and 5-fluorouracil, at a concentration of 5.5 mu M, decreased thymidine incorporation into DNA by way of the de novo pathway (thymidylate synthase activity). The salvage pathway of DNA synthesis (thymidine kinase activity), however, was not affected by these anticancer drugs. Bidisomide up to 1 mM did not affect the folate-dependent thymidylate synthase activity, nor the thymidine kinase activity of isolated rat bone marrow cells.