Microperoxisomes in type II pneumocytes and interstitial cells of postnatal rat lungs

Microperoxisomes in alveolar type II pneumocytes and lipid interstitial cells are visualized using the diaminobenzidine method for catalase. These organelles, with a diameter ranging from 100-800 nm, respectively 200-500 nm, and with no crystalline cores or densities, are in close relation with the endoplasmic reticulum. No luminal continuity between microperoxisomes and the endoplasmic reticulum is observed. Postfixation with unbuffered ferrocyanide-reduced osmiumtetroxide contributes to a better localization of microperoxisomes in both celltypes.