Glucose, lactate, and palmitate as substrates for the resting cardiac myocyte.

Cultured adult cardiac myocytes oxidize fatty acids and lactate preferentially to glucose. In contrast to other results obtained with isolated cardiac myocytes the preference for fatty acids is not dependent on carnitine administration, suggesting that the cells of this preparation possess sufficient reserves of carnitine and an intact mechanism for fatty acid activation. It is demonstrated by the substrate oxidation rates that these quiescent cells are in a state of minimal metabolic demand, thus resembling the arrested myocardium.