IMMUNOHISTOCHEMICAL LOCALIZATION OF TRANSFORMING GROWTH-FACTOR ALPHA IN THE DEVELOPING RAT COLON

Background: Transforming growth factor α (TGF-α) is a 50-amino acid polypeptide that has been related to cell proliferation and differentiation. Methods: Proximal and distal colon from fetal, newborn, and adult rats were studied by immunohistochemical techniques using a monoclonal antibody against human and rat TGF-α. Results: Immunoreactive TGF-α (IR-TGF-α) first appeared in distal colon at 18 days of gestation when the proximal colon remained negative. At all ages studied, the staining for TGF-α at the base of the crypts in the distal colon showed a supranuclear pattern. At 22 days of gestation and until 9 days of postnatal development, the proximal colon is negative for TGF-α. From day 10 to 24 of postnatal development, IR TGF-α cells with a cytoplasmic staining were confined to the lower half of the villi. Afterwards, cells at the crypts showed supranuclear staining and cells in the surface epithelium a cytoplasmic reaction. Conclusions: Age- and region-dependent expression of TGF-α in the rat colon suggests a functional role for TGF-α in the establishment and maintenance of proliferation and differentiation during development. © 1993.