PHYSIOLOGY AND PATHOPHYSIOLOGY OF INTESTINAL-ABSORPTION
PHYSIOLOGY AND PATHOPHYSIOLOGY OF INTESTINAL-ABSORPTION
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DOI：
10.1093/ajcn/55.1.299s
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发表时间：
1992-01-01
影响因子：
7.1
通讯作者：
CASPARY, WF
中科院分区：
文献类型：
--
作者：
CASPARY, WF
碳水化合物(CHO)的最终消化和吸收发生在粘膜表面的胰腺α-淀粉酶的管腔内水解之后，这与二糖的水解和糖化作用载体系统密切相关。一般来说，钠离子转运是CHO吸收的限速步骤。吸收速度由摄入方式、食物的化学成分、胃排空、胰腺消化、肠道消化和吸收以及肠道运动决定。膳食纤维、α-淀粉酶抑制剂或α-葡萄糖苷酶抑制剂可延缓CHO的吸收。蛋白质的最终消化是通过双重机制实现的：完整的多肽吸收，然后细胞内水解成游离氨基酸(AA)，多肽被膜水解，然后吸收游离氨基酸。更复杂的是脂肪吸收的机制：乳化、脂肪分解、胶束形成、膜移位、细胞内再合成、乳糜粒形成和淋巴引流。脂肪消化中最关键的步骤是脂肪分解和胶束形成。
Final digestion and absorption of carbohydrates (CHO) occur after intraluminal hydrolysis by pancreatic alpha-amylase at the surface of the mucosal membrane in close relationship between disaccharide hydrolysis and the glucalogue carrier system. In general, Na+-dependent transport is the rate-limiting step of CHO absorption. The rate of absorption is determined by mode of ingestion, chemical composition of the meal, gastric emptying, pancreatic digestion, intestinal digestion and absorption, and intestinal motility. A delay of absorption of CHO may be achieved by dietary fibers, alpha-amylase inhibitors, or alpha-glucosidase inhibitors. Final protein digestion is achieved by a dual mechanism: intact peptide absorption with subsequent intracellular hydrolysis to free amino acids (AA) and membrane hydrolysis of peptides followed by absorption of free AA. More complex is the mechanism of lipid absorption: emulsification, lipolysis, micellar formation, membrane translocation, intracellular resynthesis, chylomicron formation, and lymphatic drainage. The most critical steps in lipid digestion are lipolysis and micellar formation.