Erlandsen Sten Even, Qvigstad Gunnar, Fossmark Reidar, Bakke Ingunn, Chen Duan, Sandvik Arne K
Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Pb 8905, N-7491 Trondheim, Norway.
Regul Pept. 2012 Aug 20;177(1-3):53-9. doi: 10.1016/j.regpep.2012.04.008. Epub 2012 May 2.
The regulated endocrine-specific protein 18 (RESP18) has previously been localized to different endocrine cells and neurons, in particular the pituitary gland and hypothalamus. It is found in the lumen of the endoplasmic reticulum and is degraded at the post-ER pre-Golgi compartment, and a role in processing of secreted peptides has been hypothesized. The present study examines localization of RESP18 in the gastrointestinal mucosa of rats by immunohistochemistry, and expression and regulation in response to hypergastrinemia induced by acid inhibition (pantoprazole), gastrin antagonism (YF476), fasting-refeeding and octreotide by mRNA measurements. RESP18 was mainly found in the gastric mucosa, but could also be detected in a few, scattered cells in the lower small intestine and in colon. In the antral mucosa, all RESP18 immunoreactivity was localized to ghrelin-producing A-like cells and gastrin-producing G-cells. In the corpus mucosa, a significant fraction, but not all of the RESP18 immunoreactive cells, were A-like cells. In both antrum and corpus, Resp18 mRNA seemed to vary similarly with the activation of the A-like cells, and in the antrum also with stimulation of the G-cells. This study demonstrates, for the first time, the localization of RESP18 to specific neuroendocrine cells of the gastrointestinal mucosa and that it seems to be regulated synchronously with the peptides secreted from these cells. This suggests that Resp18 may indeed have a functional role in the synthesis or storage of these gastrointestinal peptides.
调节性内分泌特异性蛋白18（RESP18）先前已被定位到不同的内分泌细胞和神经元，特别是垂体和下丘脑。它存在于内质网腔中，并在内质网后高尔基体前区室被降解，有人推测它在分泌肽的加工过程中起作用。本研究通过免疫组织化学检测了RESP18在大鼠胃肠道黏膜中的定位，并通过mRNA测量检测了其在酸抑制（泮托拉唑）、胃泌素拮抗（YF476）、禁食-再喂养和奥曲肽诱导的高胃泌素血症反应中的表达和调节。RESP18主要存在于胃黏膜中，但也可在小肠下段和结肠的少数散在细胞中检测到。在胃窦黏膜中，所有RESP18免疫反应性均定位于产生胃饥饿素的A样细胞和产生胃泌素的G细胞。在胃体黏膜中，相当一部分（但不是全部）RESP18免疫反应性细胞是A样细胞。在胃窦和胃体中，Resp18 mRNA似乎与A样细胞的激活变化相似，在胃窦中也与G细胞的刺激变化相似。本研究首次证明了RESP18在胃肠道黏膜特定神经内分泌细胞中的定位，并且它似乎与这些细胞分泌的肽同步调节。这表明Resp18可能确实在这些胃肠肽的合成或储存中具有功能作用。
