LOCALIZATION OF TRANSFORMING GROWTH FACTOR-ALPHA IN ADULT SYRIAN-HAMSTER TISSUES

Using the cheek pouch of the Syrian hamster as an experimental model for oral carcinogenesis, it has been shown that the expression of transforming growth factor-alpha (TGF-alpha) is consistently associated with the malignant transformation process. We have recently shown that production of TGF-alpha has been localized to normal hamster oral epithelium and bone marrow eosinophils. In this study we investigated the production of this cytokine in other normal hamster adult tissues. By using an EGF-radioreceptor assay, immunohistochemistry, Northern blot analysis, and in situ hybridization we have now further detected the presence of TGF-alpha mRNA and/or protein in the kidney, stomach, and pancreas of normal adult hamster. Together with the previously reported detection of TGF-alpha in oral mucosa and bone marrow eosinophils, these adult normal tissue/cellular sources can serve as sites of TGF-alpha-production. The availability of hamster specific reagents (cDNA and monoclonal antibodies) and the delineation of the various adult tissues that could produce TGF-alpha make the Syrian hamster a suitable model for the study of how this multifunctional cytokine can influence normal and pathological processes.