Diurnal rhythmicity in intestinal SGLT-1 function, Vmax, and mRNA expression topography
Diurnal rhythmicity in intestinal SGLT-1 function, Vmax, and mRNA expression topography
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DOI：
10.1152/ajpgi.2001.280.2.g209
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发表时间：
2001-02-01
影响因子：
4.5
通讯作者：
Rhoads, DB
中科院分区：
文献类型：
--
作者：
Tavakkolizadeh, A;Berger, UV;Rhoads, DB
肠道糖吸收的昼夜节律机制尚不清楚。为了测试这种节律性是否由Na+-葡萄糖共转运蛋白1 （SGLT-1）功能的变化引起，我们测量了根霉素抑制糖通量作为SGLT-1活性的指标。在12小时明暗循环（CT0为昼夜节律时间0小时，光照开始时间）中，每隔6小时杀死大鼠，取其空肠置于Ussing实验箱中，计算加入根连素前后3- o -甲基葡萄糖（3-OMG）的通量。3- omg引起的短路电流和吸收通量的变化在CT9时明显大于CT3时。这种增加是被苯丙素抑制的。动力学研究表明，在CT9时，SGLT-1的最大速度（V-max）显著增加。CT3和CT9之间的食物摄取量为
Mechanisms underlying the circadian rhythmicity in intestinal sugar absorption remain unclear. To test whether this rhythmicity is caused by changes in Na+-glucose cotransporter 1 (SGLT-1) function, we measured phloridzin-inhibitable sugar fluxes as an index of SGLT-1 activity. Jejunum obtained from rats killed at 6-h intervals during a 12-h light-dark cycle (CT0 is circadian time 0 h, time of light onset) were mounted in Ussing chambers, and 3-O-methylglucose (3-OMG) fluxes were calculated before and after addition of phloridzin. 3-OMG-induced change in short-circuit current and absorptive flux were significantly greater at CT9 than at CT3. This increase was phloridzin inhibitable. Kinetic studies indicated a significant increase in SGLT-1 maximal velocity (V-max) at CT9. Food intake between CT3 and CT9 was