Studies with radioactive Colchicine. I. The influence of tumors on the tissue distribution of radioactive colchicine in mice.

In spite of the many papers published on colchicine and its influence on cell division, an ac ceptable explanation for the mode of action of this drug is not yet available. There is also still much uncertainty about the action of colchicine and its derivatives on tumors. Ludford (13), using tumors and tissue culture, suggests that colchicine increases the viscosity of cell protoplasm. Northen (14), with onion root tips, found a decrease in the viscosity of proto plasm. Lettré(10) explains the action of colchicine on dividing cells by its interference with the re generation of ATP from creatine phosphate. It is probable that the mode of action of colchicine should be sought in changes produced in one or several enzymatic complexes of the cell. Boyland and Boyland (3) reported changes in metabolism and ascorbic acid content after the injection of colchicine. Bloch-Frankenthal and Back (2) found that the alkaline phosphatase is reduced in a rat tumor but not in normal tissues of the same ani mal. Hawkins and Walker (9) found that when colchicine was given to hepatectomized rats it had no effect on the total amine oxidase activity of the liver but reduced the DOPA decarboxylase to about 50 per cent. The contradictory results obtained by treating different tumors with colchicine can be summa rized by saying that it seems that the growth of some tumors can be stopped, and the neoplasm may even be brought to complete regression if