Alterations in EGF binding to acini during pancreatic regeneration in the rat

The binding of 125I-labeled epidermal growth factor (EGF) was compared in acini isolated from the regenerating remnant following 90% partial pancreatectomy (ppx) and from the pancreas of sham-pancreatectomized (sham-ppx) rats. Saturation binding studies with increasing amounts of unlabeled EGF revealed that cell-associated radioactivity was decreased in acini from the regenerating remnant by comparison to acini from sham-ppx rats. Analysis of these data indicated that binding was decreased by 35% and 27% at 3 and 7 days post-ppx, respectively. This alteration in EGF binding coincides with increased exocrine cell mitotic activity. EGF binding was normalized at 14 days post-ppx, at which time the exocrine cell mitotic activity is no longer increased (Brockenbrough et al. 1987, Diabetes). 125I-insulin binding was the same in ppx and sham-ppx acini at 3 days post-ppx. Furthermore, plasma EGF concentrations were the same in ppx and sham-ppx rats. These data indicate that EGF handling by the pancreatic acinar cell is altered during the proliferative response to ppx.