Autoradiographic analysis of label distribution in mammalian atrial and ventricular cardiocytes after exposure to tritiated leucine.

Radiolabeled leucine was used as a marker for newly synthesized proteins in rat atrial and ventricular muscle. The fate of these proteins was assessed during time-course experiments using high resolution autoradiography. Special attention was paid to the labeling pattern in the central sarcoplasmic cores of atrial cardiocytes. The data obtained are compatible with the view that these cells synthesized, concentrate, and a store a product of protein nature in a fashion similar to that observed in some secretory cell types.