Alteration of cholecystokinin receptor binding after caerulein-induced pancreatitis in rats

The alteration of CCK receptor binding on the pancreatic acini in vitro following the induction of pancreatitis was investigated in male rats. Pancreatitis was induced by administering 5 intraperitoneal injections of caerulein, 40 micrograms/kg each at hourly intervals. The uptake of [3H]-thymidine in the pancreatic acini increased on day 7 following caerulein administration. The release of amylase stimulated by CCK-8, and CCK receptor analysis using bioactive [125I]-BH-CCK-8, were performed at regeneration stage, on days 14 and 28 following the injections. The maximal release of amylase stimulated by CCK-8 was reduced on day 14 by about 40% and recovered on day 28. On day 14 there was a decrease of 60% in the number of high-affinity receptors and an increase of 161% in the number of low-affinity receptors. On day 28 there was a 128% increase in the number of low-affinity receptors. Accordingly, we suggest that the CCK receptors of the regenerating cells following caerulein-induced pancreatitis differ from those of the intact cells.