[Electron-microscopic radioautography of DNA-synthesizing cells of growing rat smooth muscle tissue].

DNA-synthesizing cells of rat stomach muscle tissue following 50% resection of the fundal part, identical cells of the vena cava after disturbance of the blood out flow, and of the appendix on contraction of the ascending part of the large intestine were studied by electron microscopic autoradiography. DNA synthesis in the differentiated myocyte nuclei of the stomach muscle tissue, and of the "activated" myocytes of the stomach and the vein was observed. There were signs of asynchronous DNA synthesis in the nuclei of some smooth muscle cells and fibroblasts.