Autoradiographic Studies and Mitosis of Heart Muscle Cells in Experimental Cardiac Hypertrophy

In order to find DNA synthesis and mitosis of heart muscle cells in experimental cardiac hypertrophy, autoradiographic studies after 3H-thymidine administration and evaluation of mitosis after colchicine treatment were made on Goldblatt rats. The labeling index of heart muscle cells and of interstitial cells in 4 hours was 0.03-0.2% and 0.25-0.7%, respectively. Concomitant mitosis of labeled heart muscle cells and of interstitial cells was found in 0-0.1% and 0.1-0.3%, respectively. The mitotic figures were scarcely found after colchicine administration. Though colchicine yields rather ambiguous results, the autoradiographic studies gave definite evidence for cell division of heart muscle cells in experimental cardiac hypertrophy.