Lactate metabolism: a new paradigm for the third millennium.

Overall, the cell-to-cell lactate shuttle has expanded far beyond its initial conception as an explanation for lactate metabolism during muscle contractions and exercise to now subsume all of the other shuttles as a grand description of the role(s) of lactate in numerous metabolic processes and pathways.

http://www.ncbi.nlm.nih.gov/pubmed/15131240