Flemström G
Am J Med. 1986 Aug 18;81(2A):18-22. doi: 10.1016/s0002-9343(86)80005-5.
Bicarbonate secretion by the surface epithelium in the stomach and duodenum maintains a nearly neutral pH in the mucus gel adherent to the surface despite acidities as high as pH 2.0 to 3.0 in the gastric lumen and pH 1.5 to 2.0 in the duodenal lumen. This strongly suggests that the alkaline secretion, together with the mucus gel, provides a first-line of protection in the stomach, and this may be the main mechanism of defense in the duodenum. Bicarbonate secretion is increased by physiologic stimuli such as sham-feeding or the presence of acid in the lumen. Endogenous mucosal production of prostaglandins is important in mediating the response to the latter. Administration of E-type prostaglandins stimulates alkaline secretion in both the stomach and duodenum and also increases the thickness of the mucus layer adherent to the mucosa. The consequent increase in surface alkalinity most likely potentiates the mucosal resistance to luminal acid and pepsin.
胃和十二指肠表面上皮分泌的碳酸氢盐可使附着于表面的黏液凝胶保持接近中性的pH值，尽管胃腔内的酸度高达pH 2.0至3.0，十二指肠腔内的酸度高达pH 1.5至2.0。这有力地表明，碱性分泌物与黏液凝胶一起在胃中提供了第一道防线，这可能是十二指肠的主要防御机制。生理刺激如假饲或腔内存在酸会增加碳酸氢盐的分泌。内源性黏膜前列腺素的产生在介导对后者的反应中很重要。给予E型前列腺素可刺激胃和十二指肠的碱性分泌，还可增加附着于黏膜的黏液层厚度。由此导致的表面碱度增加很可能增强了黏膜对腔内酸和胃蛋白酶的抵抗力。
