Low-volume 'sprint' interval training (SIT) stimulates rapid improvements in muscle oxidative capacity that are comparable to levels reached following traditional endurance training (ET) but no study has examined metabolic adaptations during exercise after these different training strategies. We hypothesized that SIT and ET would induce similar adaptations in markers of skeletal muscle carbohyd...

PURPOSE To determine whether activity of carbohydrate metabolism enzymes (aldolase, pyruvate kinase, isocitrate dehydrogenase, and malate dehydrogenase) are altered in the glaucomatous trabecular meshwork (TM) compared to controls. METHODS Tissue specimens were obtained from trabeculectomy (n=45 open angle glaucoma; Caucasian, average age 61+/-8 years of age of both genders) and from cadaver ...

In 1963, a series of elegant studies conducted by Randle et al. (1) examined the preference for fuel selection by cardiac and skeletal muscle that allowed these tissues to readily switch from glucose to fatty acid oxidation in the face of increased fatty acid availability. These seminal studies paved the way for a generation of research on mechanisms underlying preference for fuel selection in ...

Skeletal muscle displays enormous plasticity to respond to contractile activity with muscle from strength- (ST) and endurance-trained (ET) athletes representing diverse states of the adaptation continuum. Training adaptation can be viewed as the accumulation of specific proteins. Hence, the altered gene expression that allows for changes in protein concentration is of major importance for any t...

Evidence is presented in support of the hypothesis that the pyruvate dehydrogenase multienzyme complex of intact rabbit heart mitochondria may be regulated by a phosphorylation-dephosphorylation mechanism. Mitochondria incubated in the presence of pyruvate plus L-malate and either ADP or uncoupler exhibit nearly identical, rapid rates of pyruvate oxidation but possess markedly different ATP lev...

l h e pyruvate dehydrogenase kinase-catalyzed inactivation of the pyruvate dehydrogenase complex was studied using dialyzed, soluble proteins from mitochondria purified from green leaf tissue of Pisum sativum 1. seedlings. At subsaturating ATP concentrations, K+ or NH4+, but not Na+, stimulated the pyruvate dehydrogenase kinase by lowering the K,,,(ATP). Micromolar concentrations of NH4+ were r...

In isolated rat adipocytes, the insulin stimulation of pyruvate dehydrogenase can be partially inhibited by inhibitors of PI3K (phosphoinositide 3-kinase) and MEK1/2 (mitogen-activated protein kinase/extracellular signal-regulated kinase kinase). In combination, U0126 and wortmannin completely block the insulin stimulation of pyruvate dehydrogenase. It is concluded that the effect of insulin on...

Altered metabolism is one of the hallmarks of cancer cells. The best-known metabolic abnormality in cancer cells is the Warburg effect, which demonstrates an increased glycolysis even in the presence of oxygen. However, tumor-related metabolic abnormalities are not limited to altered balance between glucose fermentation and oxidative phosphorylation. Key tumor genes such as p53 and c-myc are fo...

Summary Pyruvate dehydrogenase kinases (PDK1–4) inhibit the TCA cycle by phosphorylating pyruvate complex (PDC). Here, we show that PDK family is dispensable for murine embryonic development and BCKDK serves as a compensatory mechanism inactivating PDC. First, knocked out all four Pdk genes one one. Surprisingly, total KO embryos developed were born in expected ratios but died p...