Takano K. Cytochemical localization of NAD(P)H oxidase in the myoepithelial cells of salivary and other exocrine glands. Acta Histochem Cytochem

dase, a hydrogen-peroxide generating en-zyme, has been investigated using the cerium method in several mammalian ex-ocrine glands: (a) salivary glands of the rat, Mongolian gerbil, house musk shrew and man, (b) lactating mammary glands of the rat and Mongolian gerbil and (c) exorbital lacrimal gland of the rat. The NAD(P)H oxidase activity could be exclusively localized in association with the myoepithelial cells (MEC) of all the exocrine glands examined. The reaction products in the MEC were found mostly on the plasma membranes fac-ing the neighboring cells (acinar cells, ductal cells and MEC) and in the caveolae. These localizations imply that a membrane-bound NAD(P)H oxidase specific for the MEC could exist in mammalian exocrine glands, and that it may be involved in some intercellular regulatory system between MEC and other parenchymal cells of the glands. With regard to the reactivities on MEC, there were apparent diversities among different glands. Intense and constant activities were found in both the lactating mammary glands of the rat and Mongolian gerbil and the salivary glands of house musk shrew, in which the MEC are extremely developed. The usefulness of NAD(P)H oxidase as a marker enzyme of MEC and the significance of its localization in MEC are discussed