Koelz H R, Hersey S J, Sachs G, Chew C S
Am J Physiol. 1982 Sep;243(3):G218-25. doi: 10.1152/ajpgi.1982.243.3.G218.
The in vitro release of pepsinogen was studied using a preparation of isolated gastric glands from rabbits. The pepsinogen content of the glands was estimated to be about 700 U/mg dry wt. Spontaneous release of pepsinogen was found to be less than 1% of the total per hour and relatively constant for at least 2 h. Pepsinogen release was stimulated in a dose-dependent manner by both carbachol and isoproterenol. The cholinergic and beta-adrenergic stimulation was selectively inhibited by atropine and propranolol, respectively. Removal of external calcium inhibited the responses to both isoproterenol (partially) and carbachol (completely). Several agents, including histamine, prostaglandin (E2), and synthetic secretin, were found not to stimulate pepsinogen release. However, a crude secretin preparation (Boots) was found to produce significant stimulation. Dibutyryl cAMP increased pepsinogen release in a dose-dependent manner. Isoproterenol was found to increase the cAMP content of gastric glands and to stimulate adenylyl cyclase activity in homogenates. The beta-adrenergic stimulation of adenylyl cyclase was found to be selective for a population of gastric cells that was relatively depleted of parietal cells and distinct from the histamine-stimulated adenylyl cyclase activity. The results indicate that pepsinogen secretion by the gastric chief cell is regulated, in part, by separate cholinergic and beta-adrenergic mechanisms and that both calcium and cAMP play a role in this regulation.
采用兔离体胃腺制备物研究了胃蛋白酶原的体外释放。腺体内胃蛋白酶原含量估计约为700 U/mg干重。发现胃蛋白酶原的自发释放量每小时少于总量的1%，且至少2小时内相对恒定。卡巴胆碱和异丙肾上腺素均以剂量依赖方式刺激胃蛋白酶原释放。胆碱能和β-肾上腺素能刺激分别被阿托品和普萘洛尔选择性抑制。去除细胞外钙抑制了对异丙肾上腺素（部分）和卡巴胆碱（完全）的反应。发现包括组胺、前列腺素（E2）和合成促胰液素在内的几种药物不刺激胃蛋白酶原释放。然而，发现一种粗制促胰液素制剂（Boots）可产生显著刺激。二丁酰环磷腺苷以剂量依赖方式增加胃蛋白酶原释放。发现异丙肾上腺素可增加胃腺的环磷腺苷含量并刺激匀浆中的腺苷酸环化酶活性。发现β-肾上腺素能对腺苷酸环化酶的刺激对壁细胞相对较少且与组胺刺激的腺苷酸环化酶活性不同的一群胃细胞具有选择性。结果表明，胃主细胞分泌胃蛋白酶原部分受胆碱能和β-肾上腺素能机制的独立调节，且钙和环磷腺苷在该调节中均起作用。
