Lactic acidosis: how is it possible?

[Aymeric]

Hello,

Many diseases are characterized by the presence of lactic acidosis, with lowered blood pH supposedly due to lactate (as in diabetes for example).
My question is: how is it possible, since lactate coming out of the lactate dehydrogenase from pyruvate is... lactate, not lactic acid. So how does lactic acidosis occur when lactate is already ionized (thus unable to further dissociate and release a proton) when produced?

Thanks.

 

[DaveC426913]

I don't really know about this, but I'll ask a naive question anyway.

Isn't lactic acidosis a metabolic issue, in the sense that, just because it can form new molecules doesn't mean that components of that molecule are always available in sufficient quantities, and in sufficient time, to prevent build up?

I'm thinking of lactate build up when you get a cramp, because processes are happening faster than the body can compensate, though it eventually catches up.

 

[Fra]

Many diseases are characterized by the presence of lactic acidosis, with lowered blood pH supposedly due to lactate (as in diabetes for example).
My question is: how is it possible, since lactate coming out of the lactate dehydrogenase from pyruvate is... lactate, not lactic acid. So how does lactic acidosis occur when lactate is already ionized (thus unable to further dissociate and release a proton) when produced?

Glycolysis and the anaerobic fermentation with the LDH enzymes takes place in the cytoplasm of for example muscles cells, not in the blood. Lactic acid is the end product and a waste that needs to be transported out of the cell. This is however transported via blood stream transport system to the liver and or kidneys? i am not sure about those details though. There is probably some medical expert here that knows. The cytoplasm and the blood stream are two different buffering systems. Whenever too much lactate is produced fast due to anaerobic energy production or when due to other diseases the system for cleaning up the excess lactate dysfunctions blood pH may drop?

I do not know about alll diseases that influence blood pH but while overproduction of lactate may seem one cause, i think many disease are also due to problems in clearing the lactate from the blood stream fast enough. That latter part has nothing todo with anaerobic fermentation per see, it has more i supposed to do with the clerance system in other organs? liver? kidney? Yeast cells have no kidneys so i never thought about that part before ;)

https://en.wikipedia.org/wiki/Lactate_shuttle_hypothesis

/Fredrik