Lorenzsonn V, Olsen W A
Gastroenterology. 1982 May;82(5 Pt 1):838-48.
Although a variety of plant lectins are consumed as part of the normal human diet and are capable of binding to intestinal cell surfaces in vitro, little information exists on their effects on intact intestine. We have studied the acute effects of intraluminal administration of wheat germ agglutinin and concanavalin A in normal rats. Both lectins caused increased shedding of brush border membrane and, at higher concentrations, reduction in surface area, acceleration of cell loss, and shortening of villi. These changes were prevented by simultaneous administration of the appropriate sugar to inhibit binding, indicating that the effects were related to binding to carbohydrate residues of intestinal cells. Similar changes of brush borders were found after intraluminal administration of antiserum to sucrase-isomaltase, a surface protein of the brush border membrane, suggesting that the lectin effects resulted from cell surface receptor-lectin interaction rather than a primary intracellular effect. Our results suggest that dietary lectins may be in part responsible for normal turnover of brush border membrane, and support, in addition, the possibility that certain intestinal diseases such as celiac sprue may be the consequence of increased levels of lectin receptor allowing a dietary lectin to exert a toxic effect.
尽管多种植物凝集素作为正常人类饮食的一部分被摄入，并且在体外能够与肠细胞表面结合，但关于它们对完整肠道的影响却知之甚少。我们研究了向正常大鼠肠腔内注射麦胚凝集素和伴刀豆球蛋白A的急性效应。两种凝集素均导致刷状缘膜脱落增加，且在较高浓度时，会使表面积减小、细胞丢失加速以及绒毛缩短。同时给予适当的糖类以抑制结合可防止这些变化，这表明这些效应与凝集素与肠细胞碳水化合物残基的结合有关。向肠腔内注射抗蔗糖酶 - 异麦芽糖酶（一种刷状缘膜表面蛋白）的抗血清后，也发现了类似的刷状缘变化，这表明凝集素的效应是由细胞表面受体 - 凝集素相互作用引起的，而非主要的细胞内效应。我们的结果表明，膳食凝集素可能在一定程度上导致刷状缘膜的正常更新，此外，还支持了某些肠道疾病（如乳糜泻）可能是由于凝集素受体水平升高，使得膳食凝集素发挥毒性作用的结果这一可能性。
