Dietary CHO and stimulation of carbohydrases along villus column of fasted rat jejunum.
Dietary CHO and stimulation of carbohydrases along villus column of fasted rat jejunum.
复制标题
饮食 CHO 和对禁食大鼠空肠绒毛柱糖酶的刺激。
DOI：
10.1152/ajpgi.1989.256.1.g158
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Tsuboi,KK
中科院分区：
文献类型：
--
作者：
Morrill,JS;Kwong,LK;Sunshine,P;Briggs,GM;Castillo,RO;Tsuboi,KK
成年大鼠禁食4 d后，连续24 h饲喂70%蔗糖或葡萄糖的高碳水化合物饲料，肠道蔗糖酶-异麦芽糖酶（EC 3.2.1.48, EC 3.2.1.10）和麦芽糖酶-葡萄糖淀粉酶（EC 3.2.1.20）浓度升高，而乳糖酶-苯丙素水解酶（EC 3.2.1.23, EC 3.2.1.62）浓度升高。这些酶的浓度增加，其合成速率也相应加快。先前的研究表明，禁食肠内的上绒毛细胞对重新喂食高蔗糖饮食对蔗糖酶活性的刺激没有反应，与此相反，蔗糖-异麦芽糖酶和麦芽糖酶-葡萄糖淀粉酶的浓度增加被发现发生在沿绒毛柱长度的细胞中。早期的研究不同于目前的研究，基于酶的测定相对于蛋白质，而不是绒毛细胞组分的DNA含量。我们已经证明，绒毛细胞在向绒毛尖端迁移的过程中，其蛋白质含量增加了数倍，这为之前和现在的发现之间的差异提供了基础。高碳水化合物对蔗糖-异麦芽糖酶和麦芽糖-葡萄糖淀粉酶的刺激并不局限于隐窝和较低的绒毛区域，这一发现进一步证明了这一点，即它们的合成速率似乎在绒毛柱的长度上受到同样的刺激。
Adult rats when fed a high carbohydrate diet of 70% sucrose or glucose for 24 h following a 4-day fast showed increased concentrations of intestinal sucrase-isomaltase (EC 3.2.1.48, EC 3.2.1.10) and maltase-glucoamylase (EC 3.2.1.20) but not lactase-phlorizin hydrolase (EC 3.2.1.23, EC 3.2.1.62). The concentration increases of these enzymes were accompanied by corresponding acceleration of their synthesis rates. Contrary to earlier studies by others, suggesting that upper villus cells in the fasted intestine are unresponsive to stimulation of sucrase activity by refeeding a high-sucrose diet, the concentration increases of both sucrase-isomaltase and maltase-glucoamylase were seen to occur in cells all along the length of the villus column. The earlier studies differed from the present study by basing enzyme assays relative to protein rather than the DNA content of villus cell fractions. We have shown that villus cells increase their protein content severalfold while migrating to villus tip, providing the basis for the difference between earlier and the present findings. Further evidence that stimulation of sucrase-isomaltase and maltase-glucoamylase by high carbohydrate is not restricted to the crypt and lower villus region was obtained by the finding that their synthesis rates appeared to be equally stimulated along the length of the villus column.