Comparative Investigation of Methods for Determination of Lactic Acid in Blood and in Tissue Extracts

Abstract

Three different methods of lactic acid assay were compared with respect to specificity, sensitivity, quantitative recovery, and methodologic error. Analyses were carried out in known lactic acid solutions and in extracts from blood, smooth and striated muscle, and rabbit intestine, both with and without addition of lactic acid. The degree to which various substances interfered with determination by the different methods was also studied. Enzymatic determination of lactic acid by means of lactic dehydrogenase from rabbit muscle consistently proved to be the most specific, the most sensitive and, as regards quantitative recovery, the best method. It was subject, moreover, to only a small methodologic error. Determination ad modum Friedemann & Graeser (1933), while yielding fully acceptable values, was inferior to the enzymatic method in the above respects. The method of Barker & Summerson (1941) involved such a large methodologic error that results obtained with that procedure should be evaluated with circumspection. Certain divergences between our results and those of other authors in regard to the effect of sympathomimetic amines on the lactic acid content of blood and of tissue could well be attributable to the use, by those authors, of the Barker-Summerson method.