Effects of Colchicine and Colchemid on Synthesis of Deoxyribonucleic Acid in the Skin of the Guinea Pig's Ear in vitro

Abstract

COLCHICINE and colchemid have been used extensively in vivo and in vitro as a means of halting cells at metaphase in order to make the counting of mitotic figures easier. It is generally assumed that both have a fairly specific action in this respect, although colchicine is considered to be more toxic to the whole animal than colchemid. Experiments were performed to determine whether colchicine and colchemid, at the concentrations normally used, had any direct and immediate action on the initiation and rate of DNA synthesis in guinea pig epidermal cells as measured by tritiated thymidine and autoradiography, since any such effect would alter the number of cells collected at metaphase.