[Effect of thyroxine on the integrity of chromosomes].

Some features of the mechanism of thyroxin (T4) mutagenic effect in the culture of the human peripheral blood lymphocytes and the rat liver in vivo were studied. It was shown, that T4 mutagenic effect, discovered previously in the entire organism, can be stipulated by direct hormone-cell interaction. T4 mutagenic effect is associated with a change in DNA-dependent RNA polymerase activity and is realized during different phases of the cellular cycle. T4 modifying influence upon chromosome entirety is substantially limited by the age.