Epidermal growth factor binding and biologic effects on mouse pancreatic acini.

We have examined the receptor binding of radio-iodinated murine epidermal growth factor and the effects of epidermal growth factor on both amylase release and incorporation of [3H]leucine into protein in isolated adult mouse pancreatic acini in primary culture. Binding of radioiodinated murine epidermal growth factor was specific, saturable, and reversible at 37 degrees C. Analysis of competitive inhibition plots was consistent with single class of receptors with a dissociation constant of 4.0 X 10(-10) M and a binding capacity of 40,000 sites per cell. The binding of epidermal growth factor by acini was accompanied by minimal degradation of the peptide present in the medium or of that associated with the cells. Epidermal growth factor increased the basal and cholecystokinin-octapeptide-stimulated release of amylase from cultured acini with half-maximal effects at 1.5 X 10(-10) M. This effect on amylase release required a relatively long exposure to epidermal growth factor, being half-maximal after 3 h and maximal after 10 h. Epidermal growth factor also increased the incorporation of [3H]leucine into protein with a half-maximal effect at 3.0 X 10(-10) M. This effect was half-maximal after 2.5 h and maximal in 8-10 h. These data, therefore, suggest that epidermal growth factor may have a physiologic role in regulating the exocrine pancreas.