Alterations in energy metabolism of hypertrophied rat cardiomyocytes: influence of propionyl-L-carnitine.
Alterations in energy metabolism, reduced fatty acid oxidation, and cardiac carnitine content have been implicated in the evolution from compensated to decompensated cardiac hypertrophy. We determined high-energy nucleotide levels in hypertrophied quiescent cardiomyocytes isolated from rat hearts 4 weeks after banding of abdominal aorta. In hypertrophied quiescent cardiomyocytes, a decrease in ATP content (p = 0.03), and ratios of ATP/total adenine nucleotides and of ATP/ADP were observed, together with an increase in ADP. In addition, palmitate, but not glucose oxidation, was markedly reduced in hypertrophied myocytes. In the presence of 25 microM propionyl-L-carnitine (PLC) or L-carnitine (LC), 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 uptake was 50% lower than that of LC. Changes in the energy generating system of quiescent myocytes occur early in pressure overload hypertrophy, and these alterations can be attenuated by PLC.
Torielli
L
L
Prassis-Sigma Tau Research Institute, Milan, Italy.
Conti
F
F
Cinato
E
E
Ceppi
E
E
Anversa
P
P
Bianchi
G
G
Ferrari
P
P
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D006332:Cardiomegaly / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism; D002316:Cardiotonic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002331:Carnitine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D048429:Cell Size / Q000187:drug effects; D004195:Disease Models, Animal; D004734:Energy Metabolism / Q000187:drug effects*; D005227:Fatty Acids / Q000378:metabolism; D005947:Glucose / Q000737:chemistry / Q000378:metabolism; D006321:Heart / Q000187:drug effects*; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism; D010084:Oxidation-Reduction; D010168:Palmitates / Q000737:chemistry / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D051381:Rats; D011921:Rats, Inbred WKY
D002316:Cardiotonic Agents; D005227:Fatty Acids; D010168:Palmitates; D010725:Phosphocreatine; C003223:propionylcarnitine; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D005947:Glucose; D002331:Carnitine