Mulder H, Ahrén B, Karlsson S, Sundler F
Department of Physiology and Neuroscience, University of Lund, Sweden.
Regul Pept. 1996 Apr 23;62(2-3):107-12. doi: 10.1016/0167-0115(96)00005-5.
Adrenomedullin is a novel hypotensive adrenal polypeptide originally isolated from a human pheochromocytoma and is structurally related to calcitonin gene-related peptide and islet amyloid polypeptide. Using immunocytochemistry, the occurrence of adrenomedullin in the adrenal gland and gastro-entero-pancreatic region in the rat was examined and its effect on insulin secretion from isolated rat islets was determined. Adrenomedullin-like immunoreactivity occurred in noradrenaline- and adrenaline-producing cells in the adrenal gland. Gastrointestinal endocrine cells, with increased density distally, displayed adrenomedullin-like immunoreactivity; these cells constituted a subpopulation of the enterochromaffin (serotonin-containing) cells. Co-localization of adrenomedullin with somatostatin, glicentin, gastrin/cholecystokinin, peptide YY or islet amyloid polypeptide was not encountered. Adrenomedullin-immunoreactive cells were not observed in the pancreatic islets. At 1, 10 and 100 nmol/l, adrenomedullin stimulated insulin release from isolated rat islets in the presence of 3.3 mmol/l glucose (P < 0.05) and at 100 nmol/l, the peptide potentiated insulin secretion also in the presence of 8.3 mmol/l glucose (P < 0.05). These findings suggest that, besides being an adrenal hypotensive peptide, adrenomedullin may be a gut hormone with a potential insulinotropic function.
肾上腺髓质素是一种新型的降压肾上腺多肽，最初从人嗜铬细胞瘤中分离出来，在结构上与降钙素基因相关肽和胰岛淀粉样多肽有关。利用免疫细胞化学技术，研究了肾上腺髓质素在大鼠肾上腺及胃肠胰区域的存在情况，并测定了其对分离的大鼠胰岛胰岛素分泌的影响。肾上腺髓质素样免疫反应出现在肾上腺中产生去甲肾上腺素和肾上腺素的细胞中。胃肠道内分泌细胞，远端密度增加，显示出肾上腺髓质素样免疫反应；这些细胞构成肠嗜铬（含5-羟色胺）细胞的一个亚群。未发现肾上腺髓质素与生长抑素、胰高血糖素、胃泌素/胆囊收缩素、肽YY或胰岛淀粉样多肽共定位。在胰岛中未观察到肾上腺髓质素免疫反应性细胞。在3.3 mmol/l葡萄糖存在的情况下，1、10和100 nmol/l的肾上腺髓质素刺激分离的大鼠胰岛释放胰岛素（P < 0.05），在100 nmol/l时，该肽在8.3 mmol/l葡萄糖存在的情况下也增强胰岛素分泌（P < 0.05）。这些发现表明，肾上腺髓质素除了是一种肾上腺降压肽外，可能还是一种具有潜在促胰岛素分泌功能的肠道激素。
