A 32P-labeled pyruvate kinase (L-type isozyme) was elicited in response to glucagon and has been isolated from suspensions of hepatocytes incubated with inorganic [32P]phosphate. The pyruvate kinase in crude extracts of hepatocytes was stabilized by ammonium sulfate fractionation, 30% glycerol, and 50 mM KF and the enzyme was isolated by immunoprecipitation with anti-liver pyruvate kinase immun...

Weight loss associated with tumor burden has been postulated to be due to an energy imbalance resulting from increased hepatic gluconeogenesis secondary to Cori cycle activity. The mechanisms which control pyruvate metabolism are inherent to the control of gluconeogenesis in the liver. Therefore, the metabolism of pyruvate was evaluated in a transplanted tumor model in rodents which has previou...

Pyruvate dehydrogenase is a mitochondrial multienzyme complex that catalyzes the conversion of pyruvate to acetyl-coenzyme A and regulates the entry of carbohydrate into the tricarboxylic acid cycle for oxidation. During exercise, pyruvate dehydrogenase activation in human skeletal muscle is proportional to the relative aerobic power output (percent VO2max) and is regulated by increases in Ca2+...

tions (,10-3 M) of pyruvate will induce prompt and sustained stimulation of sodium transport. Only pyruvate and, to a lesser extent, those substrates known to yield pyruvate during the course of their metabolism, i.e., glucose, lactate, and oxalacetate, have been found to possess this stimulatory effect in the aldosteronetreated bladder. Possibile mechanisms for this effect of pyruvate are cons...

pyruvate spectrum acquired prior to imaging. Figure 1: (a) The C pyruvate peak image. (b) The water image showing the 3 syringe phantom. Syringe 1 contained tap water, syringe 2 contained hyperpolarized pyruvate, and syringe 3 contained 3.27M urea at thermal equilibrium and 5 mM gadodiamide and therefore has signal enhancement. (c) Carbon spectra from the pyruvate syringe and (d) carbon spectra...

Pyruvate constitutes a critical branch point in cellular carbon metabolism. We have identified two proteins, Mpc1 and Mpc2, as essential for mitochondrial pyruvate transport in yeast, Drosophila, and humans. Mpc1 and Mpc2 associate to form an ~150-kilodalton complex in the inner mitochondrial membrane. Yeast and Drosophila mutants lacking MPC1 display impaired pyruvate metabolism, with an accum...

Using analytical data and the results of degradation of glucose, lactate, and glutamate produced from [Z-14C]pyruvate or lactate, we have estimated the pathways of carbon flow during active gluconeogenesis in the kidney cortex. This approach involves a steady state model and solution with the aid of a digital computer. By the isotopic method one can estimate the rates of pyruvate carboxylase, p...

Cancer cells usually obtain energy from a high rate of glycolysis rather than oxidative phosphorylation under normoxia as well as hypoxia. Under these circumstances, pyruvate, the end-product of glycolysis, accumulates in cancer cells. We have previously reported that pyruvate activates endothelial cells and induces angiogenesis. Here, we examined the angiogenic activity of pyruvate in tumor ce...

We describe the isotopic exchange of lactate and pyruvate after arm vein infusion of [3-(13)C]lactate in men during rest and exercise. We tested the hypothesis that working muscle (limb net lactate and pyruvate exchange) is the source of the elevated systemic lactate-to-pyruvate concentration ratio (L/P) during exercise. We also hypothesized that the isotopic equilibration between lactate and p...