Light microscopic localization of acid phosphatase in different tissue cells of the albino rat

The enzyme acid phosphatase (orthophosphoric monoester phosphohydrolase, EC 3.1 3.2), often referred to as "non-specific acid phosphomonoesterase" because of histochemical and biochemical polymorphisms and ubiquity, is one of the most thoroughly studied enzyme in mammalian tissues. The aim of the present work was to outline the functional characteristics of this enzyme by extrapolating the results of light microscopic investigations. A diffuse intracytoplasmic acid phosphatase activity was detected in the epinephrine-producing cells of the adrenal medulla. Various forms of lysosomes were observed to exert acid phosphatase activity in bronchial and bronchiolar epithelia, hepatocytes, Kupffer cells and in the walls of brain vessels. Pseudounipolar ganglion cells and certain neurons of the medulla oblongata were found to contain acid phosphatase in intracellular membrane systems. Biochemically, acid phosphatase consists of more than four isozymes each of them possessing antigenically diverse molecular forms suggesting molecular polymorphism. Histochemical and biochemical polymorphisms of acid phosphatase are considered to be due to the accommodation to the pleomorphic appearance of a sole chemical bond.