Sakata J, Asada Y, Shimokubo T, Kitani M, Inatsu H, Kitamura K, Kangawa K, Matsuo H, Sumiyoshi A, Eto T
First Department of Internal Medicine, Miyazaki Medical College, Japan.
J Gastroenterol. 1998 Dec;33(6):828-34. doi: 10.1007/s005350050183.
The aim of this study was to investigate the regional distribution, molecular forms, and gene expression of adrenomedullin in the rat gastrointestinal tract and to examine physiological changes in gastric adrenomedullin after 24-h fasting. The tissue concentration was measured by radioimmunoassay. The molecular forms were analyzed by high performance liquid chromatography. mRNA levels were quantified by Northern blotting and cells positive for adrenomedullin immunoreactivity were localized by immunohistochemistry. A high concentration of adrenomedullin was found in stomach, cecum, and colon (450-520 fmol/g wet tissue). Adrenomedullin immunoreactivity was also detected in duodenum, jejunum, and ileum (200-250 fmol/g wet tissue). Transcripts of the adrenomedullin gene were widely expressed throughout the gastrointestinal tract. The major form of adrenomedullin immunoreactivity in stomach and colon corresponded precisely with authentic adrenomedullin peptide. Adrenomedullin immunoreactive cells were present in the gastrointestinal endocrine system. The concentration and mRNA level of gastric adrenomedullin after fasting were significantly increased compared with findings in controls. Adrenomedullin is ubiquitous in the gastrointestinal tract, and may be produced by endocrine cells. The results suggest that adrenomedullin, through its potent vasodilating activity, may play some role, in the stomach including the regulation of the mucosal blood flow.
本研究的目的是调查大鼠胃肠道中肾上腺髓质素的区域分布、分子形式和基因表达，并检测禁食24小时后胃内肾上腺髓质素的生理变化。通过放射免疫测定法测量组织浓度。用高效液相色谱法分析分子形式。通过Northern印迹法定量mRNA水平，并用免疫组织化学法定位肾上腺髓质素免疫反应阳性的细胞。在胃、盲肠和结肠中发现高浓度的肾上腺髓质素（450 - 520 fmol/g湿组织）。在十二指肠、空肠和回肠中也检测到肾上腺髓质素免疫反应性（200 - 250 fmol/g湿组织）。肾上腺髓质素基因转录本在整个胃肠道中广泛表达。胃和结肠中肾上腺髓质素免疫反应性的主要形式与 authentic adrenomedullin肽精确对应。肾上腺髓质素免疫反应性细胞存在于胃肠内分泌系统中。与对照组相比，禁食后胃内肾上腺髓质素的浓度和mRNA水平显著增加。肾上腺髓质素在胃肠道中普遍存在，可能由内分泌细胞产生。结果表明，肾上腺髓质素通过其强大的血管舒张活性，可能在胃中发挥某种作用，包括调节黏膜血流。
