Effect of propionyl carnitine on energy charge and adenine nucleotide content of cardiac endothelial cells during hypoxia

Adenine mucleotide metabolism is very active in endothelial cells. These cells are very rich in Xanthine Oxidase which may produce oxygen reactive species during ischaemia and reperfusion when a high amount of adenine nucleotides may be catabolized to hypoxanthine. We investigated the effect of propionyl carnitine on energy charge and nucleotide content in cultured endothelial cells during changes in oxygen partial pressure. During hypoxia the adenine nucleotide pool and the energy charge decreased more slowly in the presence of 0.5 mM propionyl carnitine than in the absence of the compound. Furthermore during reoxygenation a more rapid increase of energy charge and adenine nucleotide concentration was observed with propionyl carnitine. These observations suggest that the presence of propionyl carnitine allows the endothelial cells to maintain their functionality and regulatory role on vessel activity for a longer time and decreases the formation of oxygen reactive species due to Xanthine Oxidase activity on hypoxanthine formed by adenine nucleotide catabolism.