Abstract
To compensate uneven section thickness in the cytophotometric determination of dehydrogenase activity demonstrated with nitroblue tetrazolium (NBT), the protein staining with naphthol yellow S (NYS) was superimposed and the amount of formazan was estimated as the ratio of tissue protein content instead of the direct correction of section thickness. The absorbance of superimposed section was measured at 700nm, 570nm and 450nm for the background amount of formazan, formazan and tissue protein, respectively. Then, the enzyme activity was expressed as a relative activity (RA) as follows:
RA=A570/(A450-A700)
where, A570 and (A450-A570) represent the amounts of formazan and tissue protein, respectively. The quantitative reliability was tested with the polyacrylamide gel film containing mouse liver soluble fraction. For rapid and semi-automatic determination of RA, a special microphotometer, tridensity-automicrophotometer (TRIDENT), was devised. The method with TRIDENT was applied to show the quantitative distribution pattern of succinate dehy-drogenase activity in various tissues. A quantitative topography has been revealed in various structural units of the liver lobule, gastric gland and muscle fiber for succinate dehydrogenase activity.
