Nucleic acid synthesis in enlarged hearts of rats with nutritional anemia

Cardiac enlargement was produced in three groups of male rats by maintaining them on a diet low in iron. Hearts from anemic rats increased approximately 100% in weight compared to hearts from normal rats. When compared to control cardiac tissue, no consistent significant changes in the concentration of DNA, RNA, or protein occurred in any of the groups. The total amount of all three constituents increased significantly in the enlarged hearts; this increase was proportional to the degree of cardiac enlargement. The data indicate that nuclear and cytoplasmic material increased equally in cardiac enlargement due to nutritional anemia. This and other observations in the literature suggest hyperplasia as the most likely explanation.