Effects of Actinomycin D and Puromycin on Chromosomes of Cultured Human Leucocytes

ACTINOMYCIN D is a potent antibiotic with cytotoxic properties in tissue cultures1–3 which has been used in the treatment of human neoplasms4–9. The action of actinomycin may depend on its capacity to bind with DNA, thus inhibiting RNA synthesis10. It has also been suggested that it is the synthesis of the DNA-primed RNA which is inhibited11. Puromycin, also an antibiotic, is believed to inhibit protein synthesis in a wide variety of organisms and tissues by causing premature release of incomplete polypeptide chains from the ribosomal system12–20.