Transport of lactate and other monocarboxylates across mammalian plasma membranes.
Level 5 - mechanism / opinion, no new human data
Narrative review of biochemical and physiological transport mechanisms
PubMed 8476015 · doi:10.1152/ajpcell.1993.264.4.C761
What was done
This narrative review summarizes physiological and biochemical evidence regarding the transport mechanisms of L-lactate, pyruvate, acetoacetate, and beta-hydroxybutyrate across mammalian plasma membranes, focusing on erythrocytes, cardiac muscle, tumor cells, and epithelia.
What was found
L-lactate transport is primarily mediated by H(+)-monocarboxylate cotransporters, with the erythrocyte carrier identified as a 35–50 kDa protein sensitive to alpha-cyanocinnamate derivatives and stilbene disulfonates. Related transporters in cardiac muscle and tumor cells exhibit tissue-specific substrate affinities (Km), stereoselectivity for L- over D-lactate, and inhibitor sensitivities. Intestinal and kidney luminal membranes express distinct Na(+)-monocarboxylate cotransporters for active uptake. The abstract reports no clinical or pooled numerical outcome data beyond the 35–50 kDa molecular weight range.
Why it matters
This paper delineates the physiological diversity of monocarboxylate transport systems that regulate cellular lactate clearance, ketone utilization, and metabolic flux across various mammalian tissues.
Limits
The paper is a narrative review rather than a systematic synthesis, lacking formal study selection criteria or quantitative pooling. Findings rely predominantly on bench biochemical assays and animal membrane preparations rather than clinical trials.
Cited by
- supports Monocarboxylate transporters are saturable, meaning all-lactate can block ketone transport and all-ketones can block lactate transport.