Debnam E S, Smith M W, Sharp P A, Srai S K, Turvey A, Keable S J
Department of Physiology, Royal Free Hospital School of Medicine, London, UK.
Pflugers Arch. 1995 Jun;430(2):151-9. doi: 10.1007/BF00374645.
Rats treated with streptozotocin for 17 days were used to determine the cellular origin of enhanced brush border glucose transport in the diabetic small intestine. In the jejunum of both normal and diabetic rats, phlorizin-sensitive (SGLT1-mediated) glucose transport was shown, by section autoradiography, to take place in upper villus enterocytes. The distribution of brush border SGLT1 transporters along villi, determined using immunogold cytochemistry, was similar to that found for glucose uptake. Longer villi, supporting a larger number of absorbing enterocytes in the diabetic jejunum, appeared to be responsible for increased glucose uptake in this condition. SGLT1 protein and SGLT1-mediated glucose transport were undetectable in normal distal ileal villi. However, following treatment with streptozotocin, both SGLT1 protein and SGLT1-mediated glucose transport were found to be present in basal ileal villus enterocytes. SGLT1 protein and SGLT1-mediated glucose transport both increased during enterocyte migration to the villus tip. Cellular induction of the SGLT1 transporter, as well as longer villi contribute to enhanced glucose transport in diabetic rat distal ileum. Close correlation between the positional expression of SGLT1 protein and absorptive function suggests that transporter density is an important determinant for up-regulation of sodium-dependent glucose transport in diabetes.
用链脲佐菌素处理17天的大鼠用于确定糖尿病小肠中刷状缘葡萄糖转运增强的细胞起源。通过切片放射自显影显示，在正常和糖尿病大鼠的空肠中，根皮苷敏感（SGLT1介导）的葡萄糖转运发生在上部绒毛肠上皮细胞中。使用免疫金细胞化学确定的沿绒毛的刷状缘SGLT1转运蛋白的分布与葡萄糖摄取的分布相似。较长的绒毛支持糖尿病空肠中更多的吸收性肠上皮细胞，似乎是这种情况下葡萄糖摄取增加的原因。在正常回肠远端绒毛中未检测到SGLT1蛋白和SGLT1介导的葡萄糖转运。然而，在用链脲佐菌素治疗后，发现回肠基部绒毛肠上皮细胞中同时存在SGLT1蛋白和SGLT1介导的葡萄糖转运。在肠上皮细胞向绒毛顶端迁移过程中，SGLT1蛋白和SGLT1介导的葡萄糖转运均增加。SGLT1转运蛋白的细胞诱导以及较长的绒毛有助于糖尿病大鼠回肠远端葡萄糖转运增强。SGLT1蛋白的定位表达与吸收功能之间的密切相关性表明，转运蛋白密度是糖尿病中钠依赖性葡萄糖转运上调的重要决定因素。
