Production of hyperpolarized 13CO2 from [1-13C] pyruvate in perfused liver does reflect total anaplerosis
but is not a reliable biomarker of glucose production.
(1) It is reduced to form lactate and NAD+; (2) it is oxidized by pyruvate dehydrogenase complex (PDHC) to yield acetyl-CoA; and (3) it is carboxylated by pyruvate carboxylase to form oxaloacetate for the anaplerosis
to replenish tricarboxylic acid (TCA) cycle intermediates.
Activation of PPAR[alpha] induces pyruvate dehydrogenase kinase 4 (PDK4) , which inhibits the pyruvate dehydrogenase complex, thus preventing pyruvate from glycolysis to enter mitochondria for acetyl-CoA synthesis and anaplerosis
. The net result is the blockage of TCA and fatty acid synthesis, which requires acetyl-CoA, and the slowing-down of glycolytic rate .
Hanson, "The key role of anaplerosis
and cataplerosis for citric acid cycle function," The Journal of Biological Chemistry, vol.
Also, an excess of [1, 2-[sup.13][C.sub.2]]glucose over [1, 2, 3-[sup.13]C] glucose isotopomers has been quantified by [sup.13]C NMR in mice administered with [U-[sup.13]C]propionate [13, 14], an alternative gluconeogenic substrate that, like [U-[sub.13]C]lactate, is also metabolized to glucose via the hepatic Krebs cycle and anaplerosis
(2000) In vivo quantification of parallel and bidirectional fluxes in the anaplerosis
of Corynebacterium glutamicum, Journal of Biological Chemistry 275: 35932-35941.
Exercise with low muscle glycogen augments TCA cycle anaplerosis
but impairs oxidative energy provision in humans.
Differences between mouse and rat pancreatic islets: Succinate responsiveness, malic enzyme, and anaplerosis
. Am J Physiol Endocrin Metabol 2002; 283:E302-10.
Myoadenylate deaminase deficiency does not affect muscle anaplerosis
during exhaustive exercise in humans.
Glutamine supplementation promotes anaplerosis
but not oxidative energy delivery in human skeletal muscle.
Aryl hydrocarbon receptor nuclear translocator/hypoxia-inducible factor-1[beta] plays a critical role in maintaining glucose-stimulated anaplerosis
and insulin release from pancreatic [beta]-cells.