Comments on Point:Counterpoint: Muscle lactate and H production do/do not have a 1:1 association in skeletal muscle. Lactate and acidosis yet again?

摘要

to the editor: This third debate (4) in the APS journals on the issue of lactate production and acidosis has at last narrowed the argument to a clear and manageable question: is there a 1:1 relationship between lactate and hydrogen ion production via glycolysis in muscle? The correct answer, as already noted by Dr. Sahlin both previously (see comments in Ref. 3) and today (see comments in Ref. 1), is yes, because with respect to its effect on hydrogen ion production in an aqueous solution, all that matters is the net reaction, and the only quantitatively significant net glyco-lytic reaction in muscle is just: glucose 2 lactic acid. At biological pH, lactic acid is essentially all dissociated to lactate and hydrogen ion. [Or, if one prefers the alternative Stewartian way to say the same thing (2), lactate is a strong ion.] Unfortunately, both the Point and Counterpoint obscure this simple truth by their detailed analyses of the individual steps along the glycolytic pathway. Of course, if done correctly, this approach will also yield the correct answer, as shown by Drs. Vinnakota and Kushmerick. However, were a completely different set of enzymatic steps to evolve or be devised by which glucose is converted to lactic acid, the net effect would still be exactly the same. Let us not confuse our students any further. We should bring this argument to a close.