Effect of Colchicine on Synthesis of Desoxyribonucleic Acid in Tissue Cultured Rat Fibroblasts.

Abstract

Microspectro- photometric measurements of Feulgen stained nuclei show that while mitosis in rat fibroblasts grown in vitro is being blocked by colchicine, there is a progressive increase in the percentage of class 4 nuclei containing the doubled amount of DNA. The appearance and increase of class 8 and 16 nuclei is also observed. During treatment cells are seen to enter mitosis and revert to interphase without dividing. The synthesis of DNA during treatment is calculated to proceed at the same rate as in the controls. The following scheme could explain the production of polyploid cells: Diploid cells double their DNA content prior to mitosis, enter into colchicine-blocked mitosis, revert to interphase containing the doubled amount of DNA, and then repeat the process.