Smith P H
Am J Anat. 1983 Sep;168(1):109-18. doi: 10.1002/aja.1001680111.
The distribution of cells displaying glucagonlike or gastric inhibitory polypeptide (GIP)-like immunoreactivity was examined in the pancreatic islets and gastrointestinal tracts of rats, dogs, and humans. A-cells in the pancreatic islets in all three species were stained by antisera having regional specificity for pancreatic-type glucagon, gut-type glucagon (glicentin), or GIP. Oxyntic A-cells of the gastric mucosa in dogs and humans also were stained comparably by these three antisera. In contrast, the K- and L-cells in the intestinal mucosa of those species were stained only by antisera capable of reacting with GIP or gut-type glucagon, respectively. Tests of antibody specificity showed that the GIP antiserum did not cross-react with either pancreatic- or gut-type glucagon. Likewise, the glucagon antisera showed no cross-reactivity with GIP. Hence, these findings suggest that pancreatic and gastric A-cells contain a peptide with GIP-like immunoreactivity distinct from glucagon or glicentin per se. Although the exact basis of th GIP-like immunostaining of A-cells is unknown, it may be due to the presence of a glucagon precursor sharing certain amino-acid sequences with GIP. This hypothesis is consistent with several recent investigations showing that the processing of proglucagon molecules differs between the A- and L-cells.
在大鼠、狗和人类的胰岛及胃肠道中，研究了显示胰高血糖素样或胃抑制性多肽（GIP）样免疫反应性的细胞分布。所有这三个物种的胰岛中的A细胞都被对胰腺型胰高血糖素、肠型胰高血糖素（胰高血糖素原）或GIP具有区域特异性的抗血清染色。狗和人类胃黏膜的泌酸A细胞也被这三种抗血清以类似方式染色。相比之下，这些物种肠黏膜中的K细胞和L细胞分别仅被能够与GIP或肠型胰高血糖素反应的抗血清染色。抗体特异性测试表明，GIP抗血清与胰腺型或肠型胰高血糖素均无交叉反应。同样，胰高血糖素抗血清与GIP也无交叉反应。因此，这些发现表明胰腺和胃的A细胞含有一种具有GIP样免疫反应性的肽，其不同于胰高血糖素或胰高血糖素原本身。虽然A细胞GIP样免疫染色的确切基础尚不清楚，但这可能是由于存在一种与GIP共享某些氨基酸序列的胰高血糖素前体。这一假设与最近的几项研究一致，这些研究表明胰高血糖素原分子在A细胞和L细胞中的加工过程有所不同。
