Norepinephrine stores in the hypertrophied bovine heart

Influence of hypertrophy on the cardiac stores of norepinephrine (NE) and epinephrine in different chambers of the heart were studied in calves with experimental left or right ventricular enlargement. In the control calves, concentration of NE was markedly higher in the atrial than in the ventricles, the left atrial body had a lower concentration than the right atrial body. The same was true of the left ventricular tissue compared to the right ventricular tissue. Marked depression of the cardiac NE concentration was observed in all chambers in the groups with right and left ventricular enlargement. The magnitude of changes was roughly related to the severity of the stenosis. Depletions in the concentration of NE were not noticed in the operated nonresponsive calves. By contrast, epinephrine was in small concentrations in control calves, amounting on the average to less than 10% of the amount of NE concentration in the same cardiac tissues. However, alterations in cardiac epinephrine values were not observed in the cardiac tissues obtained from animals with cardiac hypertrophy.