López J, Cuesta N, Cuttitta F, Martínez A
Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain.
Gen Comp Endocrinol. 1999 Sep;115(3):309-22. doi: 10.1006/gcen.1999.7335.
Adrenomedullin (AM) immunoreactive cells have been identified, by immunocytochemical methods, in the endocrine pancreas of seven nonmammalian vertebrate species, belonging to the cartilaginous and bony fish, amphibian, reptilian, and bird classes. The frequency and distribution of the pancreatic AM cells vary among the different animals. In most species, these cells are found scattered mainly among the exocrine component, with a few present in the islet-like structures. The distribution of AM cells in both fish species and Xenopus shows an inverse pattern, since almost every AM cell is located in the islets. In addition, the colocalization of AM with other classical pancreatic peptide immunoreactivities has been analyzed. In numerous cells, AM immunoreactivity did not colocalize with the other hormones, suggesting that AM-producing cells might constitute a new endocrine cell type in the pancreas of many species. Nevertheless, in other cells a species-specific pattern of colocalizations with insulin, somatostatin, glucagon, and pancreatic polypeptide was found, indicating that complex interactions among all these hormones may occur. In conclusion, AM represents a new regulatory peptide of the endocrine nonmammalian vertebrate pancreas, which is possibly involved in the modulation of insulin secretion and other pancreatic functions.
通过免疫细胞化学方法，在属于软骨鱼和硬骨鱼、两栖动物、爬行动物和鸟类的七种非哺乳动物脊椎动物的内分泌胰腺中鉴定出了肾上腺髓质素（AM）免疫反应性细胞。胰腺AM细胞的频率和分布在不同动物之间有所不同。在大多数物种中，这些细胞主要散在于外分泌成分中，少数存在于胰岛样结构中。鱼类和非洲爪蟾中AM细胞的分布呈现出相反的模式，因为几乎每个AM细胞都位于胰岛中。此外，还分析了AM与其他经典胰腺肽免疫反应性的共定位情况。在许多细胞中，AM免疫反应性与其他激素没有共定位，这表明产生AM的细胞可能构成许多物种胰腺中的一种新的内分泌细胞类型。然而，在其他细胞中，发现了与胰岛素、生长抑素、胰高血糖素和胰多肽共定位的物种特异性模式，这表明所有这些激素之间可能发生复杂的相互作用。总之，AM代表了非哺乳动物脊椎动物内分泌胰腺的一种新的调节肽，可能参与胰岛素分泌和其他胰腺功能的调节。
