Hoogerwerf W A, Tsao S C, Devuyst O, Levine S A, Yun C H, Yip J W, Cohen M E, Wilson P D, Lazenby A J, Tse C M, Donowitz M
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2195, USA.
Am J Physiol. 1996 Jan;270(1 Pt 1):G29-41. doi: 10.1152/ajpgi.1996.270.1.G29.
Rabbit NHE2 and NHE3 are two epithelial isoform Na+/H+ exchangers (NHE), the messages for which are found predominantly and entirely, respectively, in renal, intestinal, and gastric mucosa. The current studies used Western analysis and immunohistochemistry to identify and characterize the apical vs. basolateral membrane distribution of NHE2 and NHE3 in intestinal epithelial cells. Based on Western analysis, NHE2 and NHE3 both are present in brush-border but not basolateral membranes of small intestine. Both NHE2 and NHE3 are 85-kDa proteins. Consistent with Western analysis, NHE2 and NHE3 are immunolocalired to the brush-border but not basolateral membranes of villus epithelial cells, but not goblet cells, in human jejunum and ileum and in surface epithelial cells in the ascending and descending colon and rectum. In addition, NHE2 and NHE3 are present in small amounts in the crypt cell brush border of human jejunum, ileum, ascending and descending colon, and rectum. In rabbit jejunum, ileum, and ascending colon, NHE2 and NHE3 are present in the brush border of epithelial and not goblet cells, again much more in the villus (small intestine)/ surface cells (colon) than the crypt. NHE2 but not NHE3 is present in the brush border of rabbit descending colon surface cells and in small amounts in crypt cells. NHE2 and NHE3 are both human and rabbit small intestinal and colonic epithelial cell brush-border Na+/H+ exchanger isoforms that colocalize in all intestinal segments except rabbit descending colon, which lacks NHE3.
兔NHE2和NHE3是两种上皮型钠氢交换体（NHE），其信使核糖核酸分别主要在肾、肠道和胃黏膜中被发现。目前的研究使用蛋白质免疫印迹分析和免疫组织化学来鉴定和表征NHE2和NHE3在肠上皮细胞顶膜与基底外侧膜的分布。基于蛋白质免疫印迹分析，NHE2和NHE3均存在于小肠的刷状缘而非基底外侧膜。NHE2和NHE3均为85 kDa的蛋白质。与蛋白质免疫印迹分析结果一致，在人空肠、回肠以及升结肠、降结肠和直肠的表面上皮细胞中，NHE2和NHE3免疫定位于绒毛上皮细胞的刷状缘而非基底外侧膜，杯状细胞中则未检测到。此外，在人空肠、回肠、升结肠、降结肠和直肠的隐窝细胞刷状缘中，NHE2和NHE3含量较少。在兔空肠、回肠和升结肠中，NHE2和NHE3存在于上皮细胞而非杯状细胞的刷状缘，同样，在绒毛（小肠）/表面细胞（结肠）中的含量远高于隐窝。NHE2存在于兔降结肠表面细胞的刷状缘，在隐窝细胞中含量较少，而NHE3则未在兔降结肠表面细胞中检测到。NHE2和NHE3均是人和兔小肠及结肠上皮细胞刷状缘钠氢交换体亚型，除缺乏NHE3的兔降结肠外，它们在所有肠段均共定位。
