Suppression of DNA synthesis in mice by the anthracycline antibiotics daunorubicin, carminomycin and doxorubicin

Inhibition of DNA synthesis by rubomycin (daunorubicin), carminomycin and doxorubicin in the spleen, liver, kidneys and heart was studied on mice. The antibiotics were administered intravenously in a dose of 0.3 LD50. The inhibition level was estimated by incorporation of 3H-thymidine. The time courses of DNA synthesis inhibition by daunorubicin, carminomycin and doxorubicin markedly differed, whereas the patterns of their inhibition curves for all the organs were close. The maximum inhibition of DNA synthesis by carminomycin was observed in 6 hours. After that period it gradually restored. Doxorubicin induced the maximum inhibition of DNA synthesis in 24-48 hours after its administration. Daunorubicin induced two maxima in inhibition of DNA synthesis i. e. in 6 and 48 hours. Definite correlation between the levels of DNA synthesis inhibition by the antibiotics and their toxic action was shown.