Chronobiological characteristics of the action of thyroxine of reproduction of Ehrlich's Ascites Tumor cells

This paper studies the action of thyroxine on cell proliferation in a hyperdiploid strain of Ehrlich's Ascites Tumor (EAT) depending on clock time. Five albino mice were given an injection of tritium-thymidine in a dose of 0.5 u Ci/g body weight (specific radioactivity 4.1 Ci/mmole) one hour before sacrifice. On autoradiographs from each animal, during examination of 3000-5000 cells, the number of dividing and DNA-synthesizing cells was counted and mitotic index and radioactive index were calculated and expressed in promille. Parameters method and the results were subjected to statistical analysis by the Fisher-Student method. Differences were considered significant at the P less than 0.05 level