ULTRASTRUCTURAL-LOCALIZATION OF CARBONYL REDUCTASE IN MOUSE LUNG

The immunocytochemical localization of tetrameric carbonyl reductase i n the mouse lung was determined by an electronmicroscopical immunogold procedure using monospecific antibodies against the enzyme. The label ling of carbonyl reductase was observed within the mitochondria of the ciliated and non-ciliated cells of the bronchioles and the type II al veolar pneumocytes, and the density of labelling in the non-ciliated c ells was higher than those in the other cells. No significant labellin g was detected over other compartments of the epithelial cells. The la belling was undetectable in the type I alveolar cells, alveolar macrop hages and connective tissue cells of the lung. These results clearly i ndicate the localization of carbonyl reductase to the mitochondrial ma trix of these epithelial cells, of which the non-ciliated bronchiolar cells contained particularly high amounts of the enzyme.