Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University Kita-9, Nishi-9, Kita-ku, Sapporo 060-8589, Japan.
J Agric Food Chem. 2010 Feb 10;58(3):1927-32. doi: 10.1021/jf9035063.
We previously showed that epilactose, a nondigestible disaccharide, increased calcium (Ca) absorption in the small intestines of rats. Here, we explored the mechanism(s) underlying the epilactose-mediated promotion of Ca absorption in a ligated intestinal segment of anesthetized rats. The addition of epilactose to the luminal solution increased Ca absorption and chromium (Cr)-EDTA permeability, a paracellular indicator, with a strong correlation (R = 0.93) between these changes. Epilactose induced the phosphorylation of myosin regulatory light chains (MLCs), which is known to activate the paracellular route, without any change in the association of tight junction proteins with the actin cytoskeleton. The epilactose-mediated promotion of the Ca absorption was suppressed by specific inhibitors of myosin light chain kinase (MLCK) and Rho-associated kinase (ROCK). These results indicate that epilactose increases paracellular Ca absorption in the small intestine of rats through the induction of MLC phosphorylation via MLCK- and ROCK-dependent mechanisms.
我们之前曾表明，一种不可消化的二糖——表乳糖，可增加大鼠小肠对钙（Ca）的吸收。在此，我们在麻醉大鼠结扎肠段中探索了表乳糖介导 Ca 吸收促进作用的机制。将表乳糖添加到腔溶液中会增加 Ca 吸收和铬（Cr）-EDTA 通透性，作为细胞旁途径的指示剂，这些变化之间存在很强的相关性（R = 0.93）。表乳糖诱导肌球蛋白调节轻链（MLC）的磷酸化，这已知可激活细胞旁途径，而紧密连接蛋白与肌动蛋白细胞骨架的结合没有任何变化。肌球蛋白轻链激酶（MLCK）和 Rho 相关激酶（ROCK）的特异性抑制剂可抑制表乳糖介导的 Ca 吸收促进作用。这些结果表明，表乳糖通过 MLCK 和 ROCK 依赖性机制诱导 MLC 磷酸化，从而增加大鼠小肠的细胞旁 Ca 吸收。
