Said S I
Clin Biochem. 1984 Apr;17(2):65-7. doi: 10.1016/s0009-9120(84)90201-7.
Increasing numbers of peptides have been found in the gastrointestinal tract. Some of these are localized primarily in endocrine cells in the gastrointestinal epithelium (e.g., gastrin, secretin) or pancreatic islets (e.g., insulin, glucagon), and function chiefly as circulating hormones. Other peptides, e.g., VIP, are principally neuropeptides present mainly in nerve cells, nerve fibres and nerve terminals; they function mainly as neurotransmitters or neuromodulators. The isolation of gut peptides has usually depended on the use of characteristic bioassays. More recently, some peptides have been isolated on the basis of unique terminal amino-acid composition. Certain chemical structures are associated with typical biological actions, and several "families" of related peptides are recognized.
越来越多的肽在胃肠道中被发现。其中一些主要定位于胃肠道上皮的内分泌细胞（如胃泌素、促胰液素）或胰岛（如胰岛素、胰高血糖素），主要作为循环激素发挥作用。其他肽，如血管活性肠肽，主要是存在于神经细胞、神经纤维和神经末梢的神经肽；它们主要作为神经递质或神经调节剂发挥作用。肠道肽的分离通常依赖于使用特征性生物测定法。最近，一些肽是根据独特的末端氨基酸组成分离出来的。某些化学结构与典型的生物学作用相关，并且识别出了几个相关肽的“家族”。
