Barfull Anna, Garriga Carles, Mitjans Montserrat, Planas Joana M
Departament de Fisiologia-Divisió IV, Facultat de Farmàcia, Universitat de Barcelona, E-08028 Barcelona, Spain.
Am J Physiol Gastrointest Liver Physiol. 2002 Mar;282(3):G559-64. doi: 10.1152/ajpgi.00262.2001.
To evaluate the effect of age on sugar transport, we determined the uptake of methyl alpha-D-glucopyranoside and the abundance of the Na(+)-D-glucose cotransporter (SGLT1) in jejunal brush-border membrane (BBM) vesicles of 2-day- and 5-wk-old chickens. Methyl alpha-D-glucopyranoside transport per BBM protein was 40% lower in adults than in newly hatched chickens. This finding was matched by parallel declines in site density of SGLT1, which were detected by Western blot. The immunohistochemical study showed that SGLT1 was exclusively located in the BBM of enterocytes along the entire villus and was absent in the crypt in both age groups, and there was an 11-fold increase in the total absorptive area during development. Northern blot studies of the abundance of SGLT1 mRNA showed similar levels for the groups studied. We conclude that the age-related decline in Na(+)-dependent hexose transport per unit of BBM protein in the chicken jejunum is due to a reduction in the density of SGLT1 cotransporter and is regulated by a posttranscriptional mechanism.
为评估年龄对糖转运的影响，我们测定了2日龄和5周龄鸡空肠刷状缘膜（BBM）囊泡中α-D-甲基吡喃葡萄糖苷的摄取以及钠-葡萄糖共转运蛋白1（SGLT1）的丰度。每单位BBM蛋白的α-D-甲基吡喃葡萄糖苷转运量在成年鸡中比新孵出的鸡低40%。这一发现与通过蛋白质印迹法检测到的SGLT1位点密度的平行下降相匹配。免疫组织化学研究表明，SGLT1仅位于沿整个绒毛的肠上皮细胞的BBM中，在两个年龄组的隐窝中均不存在，并且在发育过程中总吸收面积增加了11倍。对SGLT1 mRNA丰度的Northern印迹研究表明，所研究的组水平相似。我们得出结论，鸡空肠中每单位BBM蛋白的钠依赖性己糖转运随年龄的下降是由于SGLT1共转运蛋白密度的降低，并且受转录后机制调控。
