Alpha 1-adrenergic stimulation is coupled to cardiac myocyte hypertrophy

We have investigated whether alpha 1-adrenergic stimulation is coupled to myocardial hypertrophy in adult rat ventricular cells (ARVC) in culture. Exposure of ARVC to norepinephrine (NE) caused a significant increase in [3H]-leucine incorporation and total protein content in ARVC. Prazosin totally inhibited the NE-stimulated leucine uptake by ARVC. Inhibition of spontaneous contraction of ARVC with KCl or verapamil did not prevent the stimulation of hypertrophy by NE. Protooncogene c-myc expression in ARVC was induced at 1 h after exposure to NE. Above results support the premise that activation of the alpha 1-adrenergic receptors by NE induces hypertrophy of ARVC, independent of changes in contractile activity.