ROLE OF ESTERATIC INHIBITION ON LOCALIZATION OF ESTERASE AND THE SIMULTANEOUS CYTOCHEMICAL DEMONSTRATION OF INHIBITOR SENSITIVE AND RESISTANT ENZYME SPECIES

Evidence is presented to show that the selective demonstration of perinuclear and peribiliary cytoplasmic droplets in rat kidney and liver by Holt with halogen-substituted indoxyl acetates is largely due to inhibition of a sensitive esterase in the cytoplasm in excess of the inhibition of a resistant esterase in the droplets. The inhibition comes from the incorporation of ferro-ferricyanide in the substrate medium to serve as an oxidation catalyst for the capture reaction. Analogous results were obtained by using other substrates such as α-naphthyl acetate and naphthol-AS acetate and other inhibitors such as formalin fixation, di-isopropyl fluorophosphate, NaF and arsanilate. A product of this study was the development of a method for the simultaneous cytochemical demonstration of inhibitor-sensitive and inhibitor-resistant species of esterase, by taking advantage of red and blue azo dyes that can be formed from naphthol-AS. The distribution of these two species of esterase is described in some detail in rat kidney and liver and the findings are discussed in relation to biochemical data from cell fractionation studies.