Short-term inhibition of cardiac cellular autophagy by isoproterenol.

It is shown in the present study by means of quantitative electron microscopy that the volume fraction of autophagic vacuoles is significantly reduced to about half the control value within a short time interval (about 10 min) after low dose administration of isoproterenol. The data suggest that stimulation of cardiac work is accompanied by an immediate anticatabolic reaction which can be assumed to represent an early contribution to the adaptative increase in myocardial mass known to result from long-term stimulation of cardiac work.