Huneau J F, Tomé D
INRA, Laboratoire de Nutrition Humaine et Physiologie Intestinale, Paris, France.
Reprod Nutr Dev. 1990;30(2):237-44. doi: 10.1051/rnd:19900209.
Changes in protein absorption through the intestinal mucosa occur with aging and might reflect modifications in enterocyte membrane characteristics. We have observed that bovine beta-lactoglobulin (beta-LG) was efficiently transported across the small intestine of adult rats in vitro and that 12-16% of the absorbed protein was recovered intact or as large hydrophobic peptides. Ten percent lactose-feeding resulted in decreased tissue conductance and significantly reduced (-58%, P less than 0.05) beta-LG transport across rat small intestinal mucosa. The amounts of beta-LG absorbed, either as amino acids and peptides or as intact protein, were reduced to the same extent. Therefore, the effect of lactose feeding might be related to a decrease in protein endocytosis at the brush-border level, rather than to reduced protein transport across tight junctions.
随着年龄增长，蛋白质通过肠黏膜的吸收会发生变化，这可能反映了肠上皮细胞膜特性的改变。我们观察到，牛β-乳球蛋白（β-LG）在体外能有效地穿过成年大鼠的小肠，并且吸收的蛋白质中有12-16%以完整形式或大的疏水肽形式被回收。给予10%的乳糖喂养会导致组织电导降低，并显著降低（-58%，P<0.05）β-LG跨大鼠小肠黏膜的转运。以氨基酸和肽形式或完整蛋白质形式吸收的β-LG量均减少到相同程度。因此，乳糖喂养的影响可能与刷状缘水平蛋白质内吞作用的降低有关，而不是与跨紧密连接的蛋白质转运减少有关。
