[Effect of an erythrocyte inhibitor on the in vitro incorporation of thymidine into the DNA of bone marrow cells].

The effect of an erythrocytic inhibitor obtained from patients with second polycythaemia, on the synthesis of DNA in bone marrow cells has been studied in vitro. The erythrocytic inhibitor was shown to have a specific effect. The decrease of DNA synthesis under erythraemia occurred with the dose of the inhibitor 2-3 times higher than with the dose applied in norm or under anemia. According to the results of gel-filtration and disc-electrophoresis, the inhibitor in question is a component of fraction II of polycythaemia erythrolysate with a low molecular weight. The electrophoresis mobility of this fraction in respect to albumin lies between 0.5 and 0.7. It is supposed that the inhibitor is a physiological regulator (chalone) of the erythron's cell proliferation.