In Vivo RNA Synthesis in the Hearts of Adriamycin-treated Rats¹

Data are presented which demonstrate the effect of both acute and chronic Adriamycin treatment on myocardial RNA synthesis in vivo. The results suggest that the inhibition of RNA synthesis is a transient effect following both types of treatment and that the degree and duration of this effect is dose dependent. The data further demonstrate that Adriamycin does not alter the turnover rate of RNA and that both messenger RNA and ribosomal RNA are affected. These results, interpreted in conjuction with pharmacokinetic data, permit speculation on the relationship between acute and chronic Adriamycin treatment as well as cellular ramifications with regard to the protracted, dose-dependent cardiomyopathy.