Immunohistochemical localization of transforming growth factor alpha in the developing rat colon.

Abstract

Transforming growth factor alpha (TGF-alpha) is a 50-amino acid polypeptide that has been related to cell proliferation and differentiation. Proximal and distal colon from fetal, newborn, and adult rats were studied by immunohistochemical techniques using a monoclonal antibody against human and rat TGF-alpha. Immunoreactive TGF-alpha (IR-TGF-alpha) first appeared in distal colon at 18 days of gestation when the proximal colon remained negative. At all ages studied, the staining for TGF-alpha 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-alpha. From day 10 to 24 of postnatal development, IR TGF-alpha 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. Age- and region-dependent expression of TGF-alpha in the rat colon suggests a functional role for TGF-alpha in the establishment and maintenance of proliferation and differentiation during development.