Gromova L V, Gruzdkov A A, Gruzdkov A A
I. P. Pavlov Institute of Physiology, Russian Acad. Sci., St. Petersburg, 199034, Nab. Makarova, 6.
Ross Fiziol Zh Im I M Sechenova. 2002 Apr;88(4):510-8.
"True" (corrected for the influence of the pre-epithelial layer) kinetic constants of maltose hydrolysis (Km and Vmax) and Glucose active transport (Kt and Jmax) in the isolated loop of the rat small intestine in chronic experiments were determined using a new mathematical approach. The Km (4.260.25 mM) does not differ from that, obtained in in vitro experiments on the homogenates of mucous membrane taken from the same intestinal loops, and the Vmax (0.72 +/- 0.07 mol/(min.cm)) is 1.7 times lower than that in in vitro experiments. The Kt and Jmax values are 3.18 +/- 0.68 mM and 0.73 +/- 0.07 mol/(min.cm), resp. The estimated values of Km, Kt and Vmax are in accordance with the corresponding published data, whereas the Jmax is several times higher than the value generally believed on the basis of acute experiments in vivo. A high level of glucose absorption in the small intestine of unanesthetized animals is achieved mainly due to a high permeability of the pre-epithelial layer and a high capacity of the active transport as a major mechanism of glucose absorption in the small intestine under normal conditions.
在慢性实验中，采用一种新的数学方法测定了大鼠小肠离体肠袢中麦芽糖水解（Km和Vmax）以及葡萄糖主动转运（Kt和Jmax）的“真实”（校正了上皮前层的影响）动力学常数。Km（4.26±0.25 mM）与在取自相同肠袢的黏膜匀浆的体外实验中获得的值无差异，而Vmax（0.72±0.07 mol/(min·cm)）比体外实验中的值低1.7倍。Kt和Jmax值分别为3.18±0.68 mM和0.73±0.07 mol/(min·cm)。Km、Kt和Vmax的估计值与相应的已发表数据一致，而Jmax比基于体内急性实验通常认为的值高几倍。未麻醉动物小肠中高水平的葡萄糖吸收主要归因于上皮前层的高通透性以及主动转运的高能力，这是正常条件下小肠中葡萄糖吸收的主要机制。
