Effect of adriamycin on the polyribosome and messenger-RNA content of rat heart muscle.

The myocardial contents of DNA, protein, total and polyribosomal RNA, messenger RNA (mRNA) and polyribosomes were determined in normal and adriamycin-treated rats. While the myocardial contents of DNA and protein changed only little in adriamycin-treated rats, total and polyribosomal RNA decreased by 23.2% and 35%, mRNA and polyribosomes by 51.6% and 38.7%. Size distribution and protein synthetic activity of the polyribosome preparations obtained remained unchanged in the adriamycin-treated rats. We conclude that the reduced myocardial contents of RNA, mRNA and polyribosomes cause the previously observed impairment of myocardial protein synthesis in adriamycin-treated rats and might be important in the pathogenesis of the adriamycin-cardiomyopathy.