Analysis of mechanism on gastrin biosynthesis and secretion

胃泌素（Gastrin）是一种刺激胃酸分泌的胃肠激素，在消化性溃疡的发病机制中起重要作用，1964年Gregory和Tracy首次从猪胃窦粘膜中分离到胃泌素，它也是一种羧基端α-酰胺化的多肽激素。胃泌素酰胺化位点的前体结构为-Phe-Gly-Arg-Ser，最近，用抗前胃泌素合成肽类似物Tyr-Gly-Try-Met-Asp-Phe-Gly的单克隆抗体，通过放射免疫分析鉴定出羧基末端甘氨酸延伸的前胃泌素（gastrin-G）。本研究用单克隆抗体检测了胃泌素-G的分泌和生物合成。胃泌素的翻译后加工可能通过前胃泌素蛋白水解裂解为胃泌素-G，然后通过α-酰胺化活化而顺序发生。胃泌素-G与胃泌素共存于胃窦胃泌素细胞中，并在各种刺激下共同分泌。

Gastrin, one of well-known Gut hormon, stimulates gastric acid secretion and plays an important role in the pathogenesis of peptic ulcer.In 1964 Gregory and Tracy isolated gastrin for the first time from antrum mucosa of pig stomach.Gastrin is also one of polypeptide hormones that are alpha-amidated at the COOH-terminus. The precursor structure of gastrin at the amidation site is -Phe-Gly-Arg-Ser. Recently, COOH-terminal glycine extended progastrin (gastrin-G) were identified using radioimmunoassay with monoclonal antibody developed against a synthetic peptide analogue for progastrin, Tyr-Gly-Try-Met-Asp-Phe-Gly. Secretion and biosynthesis of gastrin-G were examined using the monoclonal antibody in the present study. Post-translational processing of gastrin might occur sequentially through proteolytic cleavage of progastrin to gastrin-G followed by activation via alpha-amidation. Gastrin-G co-existed with gastrin in antral gastrin cells, and co-secreted with gastrin in response to various stimulation from gastrin cells.