Immunoreactive Human Epidermal Growth Factor in Human Pancreatic Juice*

Abstract

Human epidermal growth factor (hEGF), which stimulates the growth of a variety of cells in culture, has recently been isolated from human urine. In the present study, we identified significant amounts of immunoreactive (IR) hEGF (mean +/- SE, 2.3 +/- 0.09 ng/ml; n = 3) in human pancreatic juice. The IR-hEGF materials were immunologically indistinguishable from standard hEGF, although they were only 5% as active in receptor binding to human placental membrane as in RIA. Gel exclusion chromatography of the pancreatic juice under neutral and acidic conditions revealed three distinct IR-hEGF components with different molecular sizes. Incubation of 125I-labeled hEGF with either the pancreatic juice or the high molecular weight component(s) yielded no aggregation or degradation products. These data suggest that fully immunoreactive but much less bioactive hEGF-like substances which are heterogeneous in size are secreted into human pancreatic juice. Their tissue(s) of origin and physiological functions, if any, remain to be elucidated.