Miyazaki K, Funakoshi A
Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Gastroenterology. 1988 Mar;94(3):745-9. doi: 10.1016/0016-5085(88)90249-1.
The secretion of pancreatic polypeptide (PP) by neuropeptides [vasoactive intestinal polypeptide, gastrin-releasing peptide (GRP), neuromedin B, and neuromedin C] and carbachol was investigated using the isolated perfused ventral part of the rat pancreas, with or without atropine, and a specific radioimmunoassay for rat PP. The release of PP from the dorsal part of the rat pancreas by GRP and carbachol was also studied. Carbachol and GRP stimulated, in a dose-dependent manner ranging from 10(-6) to 10(-9) M, PP secretion from the ventral part of the pancreas. Maximum responses were observed with 10(-7) to 10(-8) M carbachol and 10(-7) M GRP. The response with 10(-7) M carbachol was biphasic and was abolished by 10(-5) M atropine. The response with 10(-7) M GRP, however, was transient, monophasic, and not inhibited by atropine. Vasoactive intestinal polypeptide (10(-7) M) stimulated a weak PP secretion that was not inhibited by atropine. The potency of GRP and vasoactive intestinal polypeptide relative to carbachol at 10(-7) M was 24% and 7%, respectively. Neuromedin C had almost the same bioactivity as GRP with respect to the release of PP, whereas neuromedin B was one-third less potent than GRP and neuromedin C. The relative secretion of PP from the dorsal compared with the ventral part of the pancreas after stimulation by 10(-7) M carbachol and GRP was 19% and 22%, respectively. These data show that peptidergic nerves may play some role in PP secretion. In addition, the main source of PP to the systemic circulation may be the ventral part of the pancreas.
利用分离灌注的大鼠胰腺腹侧部分（有无阿托品）和大鼠胰多肽（PP）特异性放射免疫分析法，研究了神经肽[血管活性肠肽、胃泌素释放肽（GRP）、神经降压素B和神经降压素C]及卡巴胆碱对PP分泌的影响。还研究了GRP和卡巴胆碱对大鼠胰腺背侧部分PP释放的作用。卡巴胆碱和GRP以10⁻⁶至10⁻⁹M的剂量依赖性方式刺激胰腺腹侧部分PP分泌。在10⁻⁷至10⁻⁸M卡巴胆碱和10⁻⁷M GRP时观察到最大反应。10⁻⁷M卡巴胆碱的反应是双相的，且被10⁻⁵M阿托品消除。然而，10⁻⁷M GRP的反应是短暂的、单相的，且不被阿托品抑制。血管活性肠肽（10⁻⁷M）刺激较弱的PP分泌，且不被阿托品抑制。在10⁻⁷M时，GRP和血管活性肠肽相对于卡巴胆碱的效力分别为24%和7%。就PP释放而言，神经降压素C与GRP具有几乎相同的生物活性，而神经降压素B的效力比GRP和神经降压素C低三分之一。在10⁻⁷M卡巴胆碱和GRP刺激后，胰腺背侧与腹侧部分PP的相对分泌分别为19%和22%。这些数据表明肽能神经可能在PP分泌中起一定作用。此外，进入体循环的PP的主要来源可能是胰腺腹侧部分。
