Epidermal Growth Factor (Urogastrone) in Human Fluids: Size Heterogeneity*

Publisher Website
Google Scholar
Abstract
Epidermal growth factor (EGF) is a polypeptide hormone that has been isolated from both mouse and man and stimulates the growth of a variety of tissues. Human EGF (hEGF) is probably identical to β-urogastrone, a potent inhibitor of stimulated gastric acid secretion. EGF/urogastrone has a molecular weight of -6000. However, mouse EGF is isolated in extracts of submandibular glands as a high molecular weight (HMW) complex (mol wt, 74,000) containing 2 mol mouse EGF and 2 mol of an arginine esterase which is fully biologically active and is readily and reversibly dissociated by high salt concentration or low pH. Using hEGF RIA and EGF radioreceptor assay, the molecular sizes of immunoreactive and receptorreactive hEGF have been studied in human biological fluids. In unextracted saliva and milk, immunoreactive hEGF appeared to be mostly in the same molecular weight range as standard small molecular weight (SMW) hEGF (-6000). In urine, in addition to immunoreactive and receptor-reactive hEGF the size of SMW hEGF, a HMW hEGF was observed which did not dissociate under conditions of high salt concentration or low pH, appeared to have only about 26% of the biological potency (receptorbinding activity) of SMW hEGF, and on sodium dodecyl sulfate polyacrylamide gel electrophoresis in the presence of a reducing agent appeared to consist of two components with molecular weights of 28,000 and 33,000. HMW hEGF did not appear to be a glycoprotein, since it did not bind to a concanavalin A affinity column. Plasma generated nonparallel curves in RIA and was not further studied. The biosynthetic relationship of HMW hEGF to SMW hEGF, its chemical structure, and its physiological significance remain to be determined. (J Clin Endocrinol Metab48: 673, 1979)

This publication has 1 reference indexed in Scilit: