Effects of adriamycin on heart and skeletal muscle chromatin

Interactions between adriamycin (ADM) and chromatin from heart and skeletal muscle from 15 day-old chicken embryos were investigated. Adriamycin interacts with the DNA of chromatin and this interaction is modified by the chromatin proteins. One of the effects of this interaction is an increase in the melting temperature (Tm) of the DNA, where adriamycin is observed to increase the Tm of heart chromatin to a greater extent than skeletal muscle chromatin. Adriamycin also inhibits in vitro DNA and RNA synthesis in isolated chromatin and nuclei. This inhibition is observed to be greater in heart muscle. Inhibition of transcription in the myocardium could be a major cause of adriamycin-induced cardiomyopathy.