Here we go with some random-interesting facts about lactate and metabolism. A dynamic threat where everybody can add interesting info. (following the order) about lactate and its implication in exercise, health, and disease metabolism. #Lactatefacts by @Glut4Science and @MVAitor
Let´s start learning!
1- Glycolysis byproduct that can be produced and utilized by various (almost every) body cell. 2- Highly dynamic metabolite as it can "travel" through different intra-extra cellular compartments.
3-LDH enzyme is responsible for its oxidation and reduction to pyruvate. But it has more affinity to Pyruvate? WTF!
4.1-MCT proteins "family" in charge of its transport in different tissues (different isoforms). Specific for L-Lactate
4.2- MCTs are not only for L-lactate, but also other metabolites like pyruvate or Ketone Bodies (higher Km than Lactate, by the way). 5- ILS (intracellular lactate shuttle) + Cell-Cell lactate shuttle hypothesis support its dynamism.
6.1- It´s produced mainly in Type II fiber (highly glycolytic)
6.2- Consumed in Type I & IIa fibers = oxidation; Type IIx = glycogenesis).
6.3- It all depends on pH, muscle metabolic rate, blood flow, etc.
7- Heart´s mitochondria are big consumers of Lactate, especially during exercise. 8- Neurons can use it (preferably to others) as a fuel source: glycolysis or glycogenesis. The brain EATS lactate!
9- Skeletal muscle is the main lactate producer and consumer tissue, especially during exercise = the lactate fabric. 10- High [La-] downregulates glycolytic flux decreasing PFK´s and hexokinase´s activities.
11.1- Lactate is not only a fuel source but also a major gluconeogenic metabolite (liver, mainly).
11.2- And even a signalling molecule with important implications in metabolism and protein transcription.
11.3- It could play an important role in mitochondrial dynamics by stimulating mito. biogenesis. Exercise, training, production and oxidation, Z2, Fat max, blood [La-] and flux, eating carbohydrates... = all related concepts😊
12- It’s very difficult to compare absolute values of blood [La-] between individuals, but… the avg value among all elite/pro athletes I have tested in cycling and running, at VT1 intensity (~FatMax/slightly lower) is ~1,6mmol/L.
13- Lactate can also influence food behavior around exercise. Post-exercise appetite depression was associated with higher blood [La-] mediated by changes in GLP-1, PYY, and acylated-ghrelin. These peptides/hormones regulate appetite.
14-⬆️lactate flux in mitochondria can inhibit fatty acid lipolysis in peripheral tissues, transport into the inner membrane, and even beta-oxidation in TCA cycle.This happens through the regulation of CPT1, Malonil CoA, and Acetyl CoA.
FRUCTOSA Y RENDIMIENTO DEPORTIVO: Mucho más que 0,5 x glucosa, como dicta el ya famoso ratio 2:1 (glucosa:fructosa). Ayer escribí sobre ello en @glut4science y aquí va un hilo resumen que espero sea interesante.
Si te pido que escribas en orden de prioridad las palabras Glucosa y Fructosa, y les des el tamaño de letra que les correspondería en cuanto a valor, ¿qué harías? Seguramente la GLU 1ª y la FRU (con la mitad de tamaño) 2ª.Voy a intentar que te lo pienses un poco más la próx. vez.
La glucosa entra en el músculo mediante el transportador Glut4 que responde a 1)insulina y 2)contracción muscular (+Ca intra.). Este Glut4 es clave en el ejercicio para la entrada del sustrato REY al músculo= determina el rendimiento. Por eso tomamos Glucosa durante el ejercicio.