title: Differentiation of Clara cells and pneumocytes of the rat by means of enzyme- and immunohistochemistry.
abstract: Localization of non-specific esterases, Cu-Zn superoxide dismutase and dehydropeptidase-I, in rat lung was investigated enzyme-cytochemically or immunohistochemically. Esterase was demonstrated in Clara cells, type II pneumocytes, and septal cells (or vitamin A-storing lung cells), to a somewhat lesser extent in type I pneumocytes and ciliated epithelial cells of the bronchioles, and to a minor extent in interstitial fibroblasts of the alveolar septum. Large amounts of esterase reaction product were deposited in the rough endoplasmic reticulum and the nuclear envelope in Clara cells, type II pneumocytes, and septal cells, in addition to smaller amounts in other organelles. No reaction product was found in macrophages (histiocytes) in alveolar septi and alveolar macrophages, except for the primary lysosomes or phagolysosomes and trace amounts in the Golgi vesicles, and none in endothelial cells of alveolar blood capillaries, except for primary lysosomes. Immunolocalization of Cu-Zn superoxide dismutase was generally limited to a particular area of Clara cells. A constriction occurred in the apical cytoplasm of Clara cells between an immunoreactive dome-like protrusion and the non-immunoreactive cytoplasm of the supranuclear area, and the dome-like protrusion appeared to be pinched off in a ball-like or oval form. Immunolocalization of dehydropeptidase-I was demonstrated in a dome-like protrusion or supranuclear area of Clara cells or throughout the cytoplasm and in the surface plasma membrane of mesothelial cells. The presence of these enzymes in Clara cells suggests a contribution to the detoxification system of the lung, together with cytochrome p-450-dependent monooxygenase systems.
authors.affiliation: Department of Anatomy, Gunma University School of Medicine, Maebashi, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kudo
mesh_terms: D000818:Animals; D001980:Bronchi / Q000166:cytology / Q000201:enzymology; D043182:Carboxylesterase; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D004150:Dipeptidases / Q000378:metabolism; D005260:Female; D006651:Histocytochemistry; D007150:Immunohistochemistry; D008658:Inactivation, Metabolic; D008168:Lung / Q000166:cytology* / Q000201:enzymology; D008297:Male; D016253:Microscopy, Immunoelectron; D051381:Rats; D013347:Subcellular Fractions / Q000201:enzymology / Q000648:ultrastructure; D013482:Superoxide Dismutase / Q000378:metabolism; D015262:Xenobiotics / Q000378:metabolism
chemical_list: D015262:Xenobiotics; D013482:Superoxide Dismutase; D002265:Carboxylic Ester Hydrolases; D043182:Carboxylesterase; D004150:Dipeptidases; C038937:dipeptidase