The levels of epidermal growth factor (EGF) mRNA in a wide range of pig tissues were measured by a RNAase-protection assay. The highest levels were found in kidney and pancreas, with lower levels in submaxillary gland, prostate gland and seminal vesicles. Immunocytochemical staining using an antiserum raised against recombinant pig EGF localized expression of the factor to the distal convoluted tubules of the kidney and to the epithelial cells lining the pancreatic and salivary ducts. The observed expression of EGF mRNA and EGF in pig tissues is consistent with a possible role for EGF in the maintenance and repair of the epithelial lining of various ductal systems.
