The antitumor antibiotic Adriamycin is a potent inhibitor of the sodium-potassium-activated adenosine triphosphatase of native heart microsomes. Adriamycin also inhibits potassium transport (although not sodium transport) in slices of kidney cortex. The effects on both the adenosine triphosphatase and ion transport are markedly reduced by Ca2+, probably by chelation of this metal by Adriamycin. These effects could provide a basis for explaining the Adriamycin cardiotoxicity as a digitalis-type toxicity.
This work was supported by Contract NCI-CM-53792 from the Division of Cancer Treatment, National Cancer Institute, NIH, Department of Health, Education and Welfare.