DISTRIBUTION OF EPIDERMAL GROWTH-FACTOR AND EPIDERMAL GROWTH-FACTOR RECEPTOR IN HUMAN LUNG - IMMUNOHISTOCHEMICAL AND IMMUNOELECTRONMICROSCOPIC STUDIES

The distribution of epidermal growth factor (EGF) and EGF receptor (EG FR) in adult human lung was examined by immunohistochemistry and immun oelectron microscopy. EGF immunoreactivity was observed in secretory g ranules and endoplasmic reticulum of serous acinar cells of bronchial glands. EGFR immunoreactivity was detected at the cell membrane of the basal cells and the bronchial surface nonciliated cells (indifferent cells) in the bronchus, the nonciliated bronchiolar cells (Clara cells ) and the type II pneumocytes in peripheral lung. These results sugges t that EGF is secreted into bronchial surface fluid from the bronchial glands and stimulates proliferation and/or differentiation of basal c ells and indifferent cells of the bronchus, although the source of EGF responsive to Clara cells and the type II pneumocytes of peripheral l ung was not determined.