Epidermal growth factor: intracellular Ca2+ inhibits its association with pancreatic acini and A431 cells.
The uptake of 125I-labeled epidermal growth factor (125I-EGF) by mouse pancreatic acini was inhibited (40-50%) by the secretagogue cholecystokinin octapeptide (CCK8). Analysis of competitive binding data showed that the apparent Kd of EGF binding increased 135% while the binding capacity was only slightly altered (30% increase). That the effect of CCK8 on acini was mediated by intracellular Ca2+ was indicated by the following: (i) Inhibition of 125I-EGF binding to acini was dose-dependent and paralleled the known abilities of CCK8, its analogs, and the cholinergic secretagogue carbachol to induce Ca2+ efflux from acini; and (ii) addition of the Ca2+ ionophore A23187 also inhibited 125I-EGF binding. In addition, EGF association with A431 cells was also inhibited by A23187 in the presence but not the absence of Ca2+.
D000818:Animals; D001667:Binding, Competitive; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004815:Epidermal Growth Factor / Q000378:metabolism*; D008297:Male; D051379:Mice; D010179:Pancreas / Q000166:cytology* / Q000378:metabolism; D012844:Sincalide / Q000494:pharmacology
D000001:Calcimycin; D004815:Epidermal Growth Factor; D012844:Sincalide; D002118:Calcium