이자효소 분비에 관여하는 세포 내 조절 단백에 대한 연구

Abstract

CCK and cholinergic agonist stimulate enzyme release from the pancreatic acini via Gprotein-mediated activation of phospholipase C. In contrast secretin and related peptides increase the level of cAMP and activate cAMP-dependent protein kinase. Camostat, a synthetic protease inhibitor, causes pancreatic hypertrophy and hyperplasia by increasing the CCK release. In this study, the secretagogue-induced changes of Intracellular proteins were examined in the dispersed pancreatic acini of rats with or without camostat treatment. Camostat(FOY-305, 200 ㎎/㎏, p,o.) was given for 4 days twice daily and the dispensed acini were prepared at 12 hours after last treatment. The profiles of Intracellular phosphopro peins were analyzed by two-dimensional gel electrophoresis after incubating the acini with 32P. The amylase release from the dispersed acini was measured. The pancreatic weight was increased to 126% of Control, while amylase activity per mg acinar protein decreased to 41% of control. The maximum response of amylase release from dispensed acini to CCK-8 of carbachol was markedly decreased(65% or 46% of control, respectively). The group of In tracellular proteins(24 kD, p.I 4.5∼8.5) was increased in quantity by camostat. CCK 8 or secretin increased phosphorylation of a protein(34 kD, pI 4.7) in camostat-treated as well as control rats. CCK-8 increased tyrosine phosphorylation in the acini of control rats. However, in camostat-treated raIns, the basal level of tyrosine phosphorylation was increased and it was rather decreased by CCK-8. Secretin had no effect on the level of tyrosine phosphorylation in acini. These results indicate that both phospholipase C and adenylate Gyclase induce phosphorylation of an intracellular acinar protein(34 kD, pI 4.7) and camostat treatment increases the basal level of tyrosine phosphorylation in acinar cells. And these results suggest that not only serine/threonine protein kinase but also protein tyrosine kinase/phosphatase are involved in the process of CCK receptor mediated stimulation secretion coupling.