Iwatsubo T, Yamazaki M, Sugiyama Y, Suzuki H, Yanai S, Kim D C, Satoh H, Miyamoto Y, Iga T, Hanano M
Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
J Pharm Sci. 1989 Jun;78(6):457-9. doi: 10.1002/jps.2600780606.
This study was designed to determine the effect of epidermal growth factor (EGF) in the lumen on the pH of the intestinal surface in the rat jejunum, which is referred to as "microclimate-pH". In the control experiment, a significant pH gradient was observed between the mucosal surface (approximately pH 6.8) and the bulk phase (approximately pH 7.3). The microclimate-pH was decreased by 0.2-0.6 pH units after addition of higher concentrations of EGF (3-100 nM) to the lumen. The microclimate-pH thus decreased recovers to the control value by replacing EGF with TES buffer, suggesting that the EGF effect is reversible. Considering that the Na+-H+ exchanger exists on the luminal membrane of the intestinal cells, the decrease in the microclimate-pH which was induced by EGF added to the luminal side may be due to the activation of Na+-H+ exchanger.
本研究旨在确定肠腔中的表皮生长因子（EGF）对大鼠空肠肠表面pH值（即“微气候pH值”）的影响。在对照实验中，观察到黏膜表面（约pH 6.8）和肠腔液相（约pH 7.3）之间存在显著的pH梯度。向肠腔中添加较高浓度的EGF（3 - 100 nM）后，微气候pH值降低了0.2 - 0.6个pH单位。通过用TES缓冲液替代EGF，降低的微气候pH值可恢复到对照值，这表明EGF的作用是可逆的。鉴于Na⁺ - H⁺交换体存在于肠细胞的腔面膜上，向肠腔侧添加EGF所诱导的微气候pH值降低可能是由于Na⁺ - H⁺交换体的激活。
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