Histochemical study of aminopeptidase M, aminopeptidase A, and gamma-glutamyltransferase in the nasal cavity of laboratory rodents andman.

The localization of aminopeptidase M (APM), aminopeptidase A (APA) and gama-glutamyltransferase (GGT) activity was studied at light microscope level in the nasal cavity organs of the laboratory rodents (rat, mouse, guinea pig) and human foetuses. All the enzymes were demonstrated histochemically in chloroform-acetone pretreated cryostat sections with application of azocoupling methods (5, 9). These membrane-bound aminopeptidases may participate in the metabolism of peptides in the nasal cavity. They have specific roles as modulators of growth and differentiation of the epithelial cells. The results revealed differences in enzyme patterns between olfactory and respiratory epithelium. GGT seemed to be present only in respiratory epithelium and in the ducts of Bowman's glands. Activity of APM and APA was found mostly in the fibrocytes which adhered to the basal membrane of the epithelium and glands.