ALTERATIONS IN ENERGY-METABOLISM OF HYPERTROPHIED RAT CARDIOMYOCYTES - INFLUENCE OF PROPIONYL-L-CARNITINE

Alterations in energy metabolism, reduced fatty acid oxidation, and ca rdiac carnitine content have been implicated in the evolution from com pensated to decompensated cardiac hypertrophy. We determined high-ener gy nucleotide levels in hypertrophied quiescent cardiomyocytes isolate d from rat hearts 4 weeks after banding of abdominal aorta. In hypertr ophied quiescent cardiomyocytes, a decrease in ATP content (p = 0.03), and ratios of ATP/total adenine nucleotides and of ATP/ADP were obser ved, together with an increase in ADP. In addition, palmitate, but not glucose oxidation, was markedly reduced in hypertrophied myocytes. In the presence of 25 mu M propionyl-L-carnitine (PLC) or L-carnitine (L C), palmitate oxidation was significantly stimulated in hypertrophied myocytes. The ATP/ADP ratio was significantly increased only with PLC. This effect was not due to an enhanced PLC uptake, since total PLC up take was 50% lower than that of LC. Changes in the energy generating s ystem of quiescent myocytes occur early in pressure overload hypertrop hy, and these alterations can be attenuated by PLC.