Azuma T, Taggart R T, Walsh J H
Gastroenterology. 1987 Aug;93(2):322-9. doi: 10.1016/0016-5085(87)91022-5.
Recently, glycine-extended processing intermediates of progastrin were identified in porcine stomach using a radioimmunoassay with conventional polyclonal antisera developed against a synthetic peptide analogue for progastrin processing intermediates, gastrin 6-G(Tyr-Gly-Trp-Met-Asp-Phe-Gly). We developed monoclonal antibodies specific for glycine-extended processing intermediates of progastrin (gastrin G). Monoclonal antibody 109-21 appeared to require the carboxyl-terminal pentapeptide structure of gastrin 6-G for maximal binding. Cross-reactivities of 109-21 against gastrin 17 I, gastrin 17 II, cholecystokinin-octapeptide, des(SO3) cholecystokinin-octapeptide, and gastrin 6-G-R-R were respectively 1%, less than 0.1%, less than 0.1%, 0.1%, and 0.5%. With this monoclonal antibody and a polyclonal gastrin antibody we examined the concentrations of gastrin and gastrin G in tissue and the effects of bombesin on the release of gastrin and gastrin G from rat antral mucosa in tissue culture. The gastrin G to gastrin ratio was 2.2 in rat antral mucosa and 0.66 in rat duodenal mucosa. In tissue culture, bombesin significantly stimulated gastrin and gastrin-G secretion at doses of 10(-8) and 3 X 10(-8) M. Atropine (10(-6) M) abolished the actions of carbachol to stimulate gastrin and gastrin-G secretion but had no effect on bombesin-stimulated gastrin and gastrin-G secretion. These results suggest that gastrin G is cosecreted with gastrin in response to carbachol and bombesin, and the stimulation of gastrin and gastrin-G secretion by bombesin does not involve cholinergic neural pathways and may reflect a direct action on gastrin cells.
最近，利用针对胃泌素加工中间体胃泌素6-G（酪氨酸-甘氨酸-色氨酸-甲硫氨酸-天冬氨酸-苯丙氨酸-甘氨酸）的合成肽类似物制备的传统多克隆抗血清进行放射免疫测定，在猪胃中鉴定出了甘氨酸延伸的胃泌素加工中间体。我们制备了对胃泌素（胃泌素G）的甘氨酸延伸加工中间体具有特异性的单克隆抗体。单克隆抗体109-21似乎需要胃泌素6-G的羧基末端五肽结构才能实现最大结合。109-21对胃泌素17 I、胃泌素17 II、胆囊收缩素八肽、去（SO3）胆囊收缩素八肽和胃泌素6-G-R-R的交叉反应率分别为1%、小于0.1%、小于0.1%、0.1%和0.5%。利用这种单克隆抗体和多克隆胃泌素抗体，我们检测了组织中胃泌素和胃泌素G的浓度，以及蛙皮素对组织培养中大鼠胃窦黏膜胃泌素和胃泌素G释放的影响。大鼠胃窦黏膜中胃泌素G与胃泌素的比值为2.2，大鼠十二指肠黏膜中为0.66。在组织培养中，蛙皮素在10^(-8)和3×10^(-8) M的剂量下显著刺激胃泌素和胃泌素-G的分泌。阿托品（10^(-6) M）消除了卡巴胆碱刺激胃泌素和胃泌素-G分泌的作用，但对蛙皮素刺激的胃泌素和胃泌素-G分泌没有影响。这些结果表明，胃泌素G与胃泌素共同分泌以响应卡巴胆碱和蛙皮素，蛙皮素对胃泌素和胃泌素-G分泌的刺激不涉及胆碱能神经通路，可能反映了对胃泌素细胞的直接作用。
