The role of mitochondrial pyruvate transport in the control of lactate gluconeogenesis.
At low L-lactate concentrations, plots of the reciprocal of the gluconeogenic rate vs hydroxycyanocinnamate concentration were linear up to high inhibitor concentrations, indicating that the pyruvate transporter was a rate-limiting step and alternate pathways were at best minor. At 10 mM L-lactate and in the absence of added acids, the 1/V vs I plots became sigmoidal, indicating both some excess capacity of the transporter, and a significant alternative pathway. Use of transaminase inhibitors suggests that the alternate pathway does not primarily involve a dual glutamate-pyruvate transaminase mechanism.
D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D001693:Biological Transport, Active / Q000187:drug effects; D003373:Coumaric Acids / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D005943:Gluconeogenesis / Q000187:drug effects; D066298:In Vitro Techniques; D007773:Lactates / Q000378:metabolism*; D019344:Lactic Acid; D008930:Mitochondria, Liver / Q000378:metabolism*; D011773:Pyruvates / Q000378:metabolism*; D019289:Pyruvic Acid; D051381:Rats
D001639:Bicarbonates; D003373:Coumaric Acids; D007773:Lactates; D011773:Pyruvates; C007175:alpha-cyano-4-hydroxycinnamate; D019344:Lactic Acid; D019289:Pyruvic Acid