[Biological effects of thyroxine in experimental carcinogenesis].

The study was undertaken to examine the in vitro and in vivo effects ofthyroxine Т4 at the concentrations of 10-4 M, 10-6 M, 10- M on the proliferative capacity and apoptosis of tumor cells of various pathogenesis. During the investigations, the authors used the unicellular suspension prepared from the surgical material obtained from 2 patients operated on for thyroid nodules (n = 1) and breast tumors in gynecomastia (n = 1) and evaluated the in vivo antitumor and antiproliferative activities of Т4, by using the melanoma B-16 inoculated in C57B1 mice. In the in vitro experiments, Т4 given in a dose of 10- М produced the highest cytotoxic activity against benign thyroid tumor cells (70±4.