Huntingtin-associated protein 1 (HAP1) is a neuronal cytoplasmic protein that is predominantly expressed in the brain and spinal cord. In addition to the central nervous system, HAP1 is also expressed in the peripheral organs including endocrine system. Different types of enteroendocrine cells (EEC) are present in the digestive organs. To date, the characterization of HAP1-immunoreactive (ir) cells remains unreported there. In the present study, the expression of HAP1 in pyloric stomach in adult male rats and its relationships with different chemical markers for EEC [gastrin, marker of gastrin (G) cells; somatostatin, marker of delta (D) cells; 5-HT, marker of enterochromaffin (EC) cells; histamine, marker of enterochromaffin-like (ECL) cells] were examined employing single- or double-labelled immunohistochemistry and with light-, fluorescence- or electron-microscopy. HAP1-ir cells were abundantly expressed in the glandular mucosa but were very few or none in the surface epithelium. Double-labelled immunofluorescence staining for HAP1 and markers for EECs showed that almost all the G-cells expressed HAP1. In contrast, HAP1 was completely lacking in D-cells, EC-cells or ECL-cells. Our current study is the first to clarify that HAP1 is selectively expressed in G-cells in rat pyloric stomach, which probably reflects HAP1’s involvement in regulation of the secretion of gastrin.

亨廷顿蛋白相关蛋白 1 (HAP1) 是一种神经元细胞质蛋白，主要在大脑和脊髓中表达。除中枢神经系统外，HAP1还在包括内分泌系统在内的外周器官中表达。消化器官中存在不同类型的肠内分泌细胞 (EEC)。迄今为止，HAP1 免疫反应性 (ir) 细胞的特征仍未报道。在本研究中，HAP1在成年雄性大鼠幽门胃中的表达及其与EEC不同化学标志物[胃泌素，胃泌素（G）细胞的标志物；生长抑素，δ（D）细胞的标志物；5-HT，肠嗜铬 (EC) 细胞的标志物；组胺，肠嗜铬样 (ECL) 细胞的标志物] 使用单标记或双标记免疫组织化学和光，荧光显微镜或电子显微镜。HAP1-ir 细胞在腺体粘膜中大量表达，但在表面上皮中很少或没有。HAP1 的双标记免疫荧光染色和 EEC 的标记表明几乎所有的 G 细胞都表达 HAP1。相比之下，HAP1 在 D 细胞、EC 细胞或 ECL 细胞中完全缺乏。我们目前的研究首次阐明HAP1在大鼠幽门胃的G细胞中选择性表达，这可能反映了HAP1参与了胃泌素分泌的调节。HAP1 完全缺乏 D 细胞、EC 细胞或 ECL 细胞。我们目前的研究首次阐明HAP1在大鼠幽门胃的G细胞中选择性表达，这可能反映了HAP1参与了胃泌素分泌的调节。HAP1 完全缺乏 D 细胞、EC 细胞或 ECL 细胞。我们目前的研究首次阐明HAP1在大鼠幽门胃的G细胞中选择性表达，这可能反映了HAP1参与了胃泌素分泌的调节。