IMMUNOLOCALIZATION OF CELLULAR GLUTATHIONE-PEROXIDASE IN ADULT-RAT LUNGS AND QUANTITATIVE-ANALYSIS AFTER POSTEMBEDDING IMMUNOGOLD LABELING

To determine the distribution of cellular glutathione peroxidase in ra t lungs, the tissues were stained immunohistochemically. Quantitative analysis was performed in certain cell types of alveolar linings, afte r the ultrathin sections were stained by a postembedding immunogold te chnique. Immunoblot analysis revealed that homogenates of rat liver, h eart, and lungs all gave a single band. Under the light microscope, th e following tissues were stained intensely: epithelial cells, smooth m uscle cells and glands of bronchi and bronchioles, type II alveolar ce lls, and alveolar macrophages. Under immunoelectron microscopy, type I I alveolar cells and macrophages were abundant in mitochondria. The mi tochondria, nucleus, and cytoplasm of macrophages were labeled almost twice as densely as the respective compartments of type II alveolar ce lls. Within cell types, the mitochondria were labeled twice as densely as the nuclei. The other particles were less than half as densely lab eled as the nuclei. The labeling was slightly less dense in the cytopl asm than in the nucleus. The present study revealed that glutathione p eroxidase occurred predominantly in the epithelial linings and metabol ically active sites in rat lungs. The tissues that were previously fou nd to be rich in superoxide dismutases were also rich in glutathione p eroxidase.