Lactate as a fulcrum of metabolism.
Level 5 - mechanism / opinion, no new human data
Narrative review of biochemical mechanisms without systematic methodology or primary human trial data.
PubMed 32113910 · doi:10.1016/j.redox.2020.101454
What was done
This narrative review summarizes physiological and biochemical evidence on the roles of the L-lactate anion in aerobic metabolism, focusing on intracellular and intercellular shuttling, mitochondrial oxidation, gluconeogenesis, cell signaling, and epigenetic modification via histone lactylation.
What was found
The abstract reports that physiological tissue lactate concentrations range from 0.5 to 20 mM, and cellular lactate-to-pyruvate ratios range from 10 to >500 during exercise and stress. Lactate modulates substrate partitioning by inhibiting adipose lipolysis through HCAR-1 and muscle mitochondrial fatty acid uptake via malonyl-CoA and CPT1. Repeated exercise-induced lactate exposure alters expression of regulatory enzymes for glycolysis and respiration. No primary trial metrics are reported.
Why it matters
It highlights the conceptual transition of lactate from a metabolic waste product of hypoxia to a key signaling molecule and regulator of whole-body energy metabolism.
Limits
As a narrative review, it lacks a systematic literature search, quantitative pooling, and direct original empirical human data.
Cited by
- context Lactate is more energetically favorable to convert into cellular energy than glucose, requiring less energy to produce ATP.