This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Desjardins, R. Articles by Busch, H. Search for Related Content PubMed PubMed Citation Articles by Desjardins, R. Articles by Busch, H.

Effects of Antitumor Agents on the Synthesis of Nucleolar DNA¹

Department of Pharmacology and the Tumor Byproducts Laboratory, Baylor University College of Medicine, Houston, Texas

In studies on labeling of DNA by tritiated thymidine, it was found that extranucleolar DNA was labeled more rapidly than nucleolar DNA. Several types of effects on labeling of DNA were produced by the antitumor agents used in this study In the 1 type, represented by the alkylating agent uracil mustard, there was an equal suppression of labeling of DNA in the nucleolar and the extranucleolar chromatin. In the 2nd type, vinblastine sulfate produced a greater inhibition of incorporation of labeled precursor into nucleolar DNA than into extranucleolar DNA. Thirdly, actinomycin D produced a slight stimulation instead of a suppression of labeling about equally in the nucleolar and the extranucleolar DNA.

¹ These studies were supported in part by grants from the American Cancer Society, the Jane Coffin Childs Fund, the National Science Foundation, and the USPHS (CA 08182).

² Postdoctoral trainee of the USPHS.

Received 5/10/66. Accepted 8/19/66.