Anaplerosis from asparagine increases ketone oxidation in isolated rat hearts in the absence of pyruvate precursors

Abstract

Myocardial ketone body oxidation in the Krebs cycle depends on anaplerosis, mainly via pyruvate from glucose and glycogen undergoing glycolysis. Inhibition of glycolysis can decrease ketone (b-hydroxybutyrate: βHB) oxidation and deplete Krebs cycle intermediates, but it is uncertain whether amino acids act as anaplerotic substrates under such circumstances. The amino acids, asparagine, valine and glutamine can be metabolised into the Krebs cycle intermediates, oxaloacetate, succinyl-CoA and a-ketoglutarate, respectively. Here, we determined whether physiological concentrations of asparagine, valine or glutamine act as anaplerotic substrates to increase βHB oxidation in isolated rat heart in the absence of pyruvate precursors.