Yoshida A, Takata K, Kasahara T, Aoyagi T, Saito S, Hirano H
Third Department of Internal Medicine, Kyorin University School of Medicine, Tokyo, Japan.
Histochem J. 1995 May;27(5):420-6.
Glucose is actively absorbed in the intestine by the action of the Na(+)-dependent glucose transporter. Using an antibody against the rabbit intestinal Na(+)-dependent glucose transporter (SGLT1), we examined the localization of SGLT1 immunohistochemically along the rat digestive tract (oesophagus, stomach, duodenum, jejunum, ileum, colon and rectum). SGLT1 was detected in the small intestine (duodenum, jejunum and ileum), but not in the oesophagus, stomach, colon or rectum. SGLT1 was localized at the brush border of the absorptive epithelium cells in the small intestine. Electron microscopical examination showed that SGLT1 was localized at the apical plasma membrane of the absorptive epithelial cells. SGLT1 was not detected at the basolateral plasma membrane. Along the crypt-villus axis, all the absorptive epithelial cells in the villus were positive for SGLT1, whose amount increased from the bottom of the villus to its tip. On the other hand, cells in the crypts exhibited little or no staining for SGLT1. Goblet cells scattered throughout the intestinal epithelium were negative for SGLT1. These observations show that SGLT1 is specific to the apical plasma membrane of differentiated absorptive epithelial cells in the small intestine, and suggest that active uptake of glucose occur mainly in the absorptive epithelial cells in the small intestine.
葡萄糖通过钠依赖性葡萄糖转运体的作用在肠道中被主动吸收。我们使用针对兔肠道钠依赖性葡萄糖转运体（SGLT1）的抗体，通过免疫组织化学方法研究了SGLT1在大鼠消化道（食管、胃、十二指肠、空肠、回肠、结肠和直肠）中的定位。在小肠（十二指肠、空肠和回肠）中检测到了SGLT1，但在食管、胃、结肠或直肠中未检测到。SGLT1定位于小肠吸收上皮细胞的刷状缘。电子显微镜检查显示，SGLT1定位于吸收上皮细胞的顶端质膜。在基底外侧质膜未检测到SGLT1。沿着隐窝-绒毛轴，绒毛中的所有吸收上皮细胞SGLT1均呈阳性，其含量从绒毛底部到顶端逐渐增加。另一方面，隐窝中的细胞对SGLT1几乎没有染色或无染色。散在于整个肠上皮的杯状细胞对SGLT1呈阴性。这些观察结果表明，SGLT1特异性定位于小肠分化吸收上皮细胞的顶端质膜，并提示葡萄糖的主动摄取主要发生在小肠的吸收上皮细胞中。
