Date Yukari, Nakazato Masamitsu, Hashiguchi Suzuko, Dezaki Katsuya, Mondal Muhtashan S, Hosoda Hiroshi, Kojima Masayasu, Kangawa Kenji, Arima Terukatsu, Matsuo Hisayuki, Yada Toshihiko, Matsukura Shigeru
Department of Internal Medicine, Miyazaki Medical College, Kiyotake, Miyazaki, Japan.
Diabetes. 2002 Jan;51(1):124-9. doi: 10.2337/diabetes.51.1.124.
Ghrelin, a novel growth hormone-releasing peptide isolated from human and rat stomach, is a 28-amino acid peptide with a posttranslational acylation modification that is indispensable for stimulating growth hormone secretion by increasing intracellular Ca(2+) concentration. It also functions in the regulation of feeding behavior, energy metabolism, and gastric acid secretion and motility. Using two different antibodies against the NH(2)- and COOH-terminal regions of ghrelin, we studied its localization in human and rat pancreas by immunohistochemistry. Ghrelin-immunoreactive cells were identified at the periphery of pancreatic islets in both species. Ghrelin co-localized exclusively with glucagon in rat islets, indicating that it is produced in alpha-cells. We identified ghrelin and des-acyl ghrelin in the rat pancreas using reverse-phase high-performance liquid chromatography combined with two radioimmunoassays. We also detected mRNA encoding ghrelin and its receptor in the rat pancreatic islets. Ghrelin increased the cytosolic free Ca(2+) concentration in beta-cells and stimulated insulin secretion when it was added to isolated rat pancreatic islets. These findings indicate that ghrelin may regulate islet function in an endocrine and/or paracrine manner.
胃饥饿素是一种从人和大鼠胃中分离出的新型生长激素释放肽，是一种含28个氨基酸的肽，具有翻译后酰化修饰，该修饰对于通过增加细胞内钙离子浓度来刺激生长激素分泌是必不可少的。它还在进食行为、能量代谢以及胃酸分泌和胃动力的调节中发挥作用。我们使用两种针对胃饥饿素氨基末端和羧基末端区域的不同抗体，通过免疫组织化学研究了其在人和大鼠胰腺中的定位。在这两个物种的胰岛周围均鉴定出了胃饥饿素免疫反应性细胞。在大鼠胰岛中，胃饥饿素仅与胰高血糖素共定位，表明它是由α细胞产生的。我们使用反相高效液相色谱结合两种放射免疫分析法在大鼠胰腺中鉴定出了胃饥饿素和去酰基胃饥饿素。我们还在大鼠胰岛中检测到了编码胃饥饿素及其受体的mRNA。当将胃饥饿素添加到分离的大鼠胰岛中时，它会增加β细胞中的胞质游离钙离子浓度并刺激胰岛素分泌。这些发现表明，胃饥饿素可能以内分泌和/或旁分泌方式调节胰岛功能。
