Cytospectrophotometric studies on the lactate dehydrogenase isoenzymes in functionally different neuron-neuroglia units. I. Optimal procedure conditions and topochemical comparisons in normal mice.

Optimal conditions are described to reveal quantitatively the total activity of lactate dehydrogenase (LDH) and the activity of its H- and M-form in the nervous tissue sections when applying Brody and Engel's tetrazolium method modified by Gerebtzoff. This histochemical reaction has been shown to obey Bouger-Lambert-Beer's law which confirms the possibility of the quantitative determination of the activity of LDH and its isoenzymes by means of cytospectrophotometric method. In the neurons of different areas of the mouse nervous system (cerebral cortex, cerebellar cortex, spinal cord anterior horns, spinal ganglia), both the total LDH activity and the activities of its H- and M-forms were localized in the cytoplasm. Within the limits of the sensitivity and correctness of the cytospectrophotometric method, the ratio of H- to M-forms of LDH did not differ significantly in the majority of the neuron types studied as well as in the neurons as compared with their glial satellite cells.