Gutschmidt S, Sandforth F, Menge H, Riecken E O
Gut. 1982 May;23(5):376-81. doi: 10.1136/gut.23.5.376.
Four and 12 days after the construction of self-filling jejunal blind loops in the rat, the apparent Km- and Vmax-values of lactase/beta-glucosidase and neutral alpha-glucosidase were determined by in-situ quantitative enzyme histochemistry, and changes in the villus-crypt architecture of the mucosa were examined by microdissection. The results were compared with corresponding data from sham-operated controls. The kinetics data were obtained from the base and the transition zone between medium and apical villus third by the use of a microdensitometric technique. The apparent Vmax of lactase/beta-glucosidase is significantly smaller than in the control rats at both measuring sites of the villi and even decreases from day 4 to day 12. The apparent Vmax of neural alpha-glucosidase is not affected, and thus the same increase in enzyme activity along the villi as in the controls is observed. The apparent Km of this enzyme, however, is already significantly increased on day 4 at both villus positions in the blind loops. A pronounced increase in villus surface area is detected in the blind loops as a result of an increase in crypt cell proliferation. The results indicate that enzymatic adaptation in the self-filling blind loops of rat jejunum exhibits different patterns for brush border alpha- and beta-glucosidases and is at least in part accomplished independently of the pronounced mucosal transformation occurring in this experimental condition.
在大鼠构建自填充空肠盲袢后的第4天和第12天，通过原位定量酶组织化学测定乳糖酶/β - 葡萄糖苷酶和中性α - 葡萄糖苷酶的表观Km值和Vmax值，并通过显微解剖检查黏膜绒毛 - 隐窝结构的变化。将结果与假手术对照组的相应数据进行比较。动力学数据是通过使用显微密度测定技术从绒毛基部以及绒毛中部和顶部三分之一之间的过渡区获得的。在绒毛的两个测量部位，乳糖酶/β - 葡萄糖苷酶的表观Vmax均显著低于对照大鼠，甚至从第4天到第12天有所下降。神经α - 葡萄糖苷酶的表观Vmax不受影响，因此观察到沿绒毛的酶活性与对照组一样增加。然而，在盲袢中，该酶的表观Km在第4天在两个绒毛位置就已经显著增加。由于隐窝细胞增殖增加，在盲袢中检测到绒毛表面积明显增加。结果表明，大鼠空肠自填充盲袢中的酶适应性对于刷状缘α - 和β - 葡萄糖苷酶表现出不同模式，并且至少部分是独立于在此实验条件下发生的明显黏膜转变而完成的。
