Smith K T, cousins R J, Silbon B L, Failla M L
J Nutr. 1978 Nov;108(11):1849-57. doi: 10.1093/jn/108.11.1849.
An isolated vascularly perfused rat intestine system was utilized to examine various aspects of zinc absorption in an attempt to more clearly examine the mechanisms involved. The lumen was perfused with a modified tissue culture medium containing 65Zn. The vascular system was perfused from the superior mesenteric artery to the portal vein, with Krebs-Ringer bicarbonate buffer containing 5% rat serum. The criterion for absorption was the amount of radioactivity transferred to the vascular perfusate. When the intestines were obtained from rats that had consumed a zinc-deficient diet the amount of zinc absorbed increased markedly. Conversely, elevation of zinc status decreased the amount of 65Zn that could be transferred to the vascular perfusate. These data strongly suggest that the isolated, perfused rat intestine retains the ability to exercise homeostatic control over 65Zn absorption. Transfer of infused 65Zn to the vascular perfusate was significantly decreased by aspirin, phytate, and prostaglandin E2. Uptake of 65Zn from the lumen into the intestinal cells was significantly increased by histidine and significantly decreased by phytate and prostaglandin E2. Thus, the isolated, vascularly perfused rat intestine appears to be capable of differentiating between the cellular uptake and cell to plasma transfer phases of zinc absorption.
利用一个分离的血管灌注大鼠肠道系统来研究锌吸收的各个方面，以便更清楚地探究其中涉及的机制。肠腔用含有65Zn的改良组织培养基灌注。血管系统从肠系膜上动脉灌注至门静脉，灌注含5%大鼠血清的 Krebs-Ringer碳酸氢盐缓冲液。吸收的标准是转移至血管灌注液中的放射性活度。当从食用缺锌饮食的大鼠获取肠道时，锌的吸收量显著增加。相反，锌状态的升高会降低可转移至血管灌注液中的65Zn量。这些数据有力地表明，分离的灌注大鼠肠道保留了对65Zn吸收进行稳态控制的能力。阿司匹林、植酸盐和前列腺素E2可显著降低注入的65Zn向血管灌注液的转移。组氨酸可显著增加65Zn从肠腔向肠细胞的摄取，而植酸盐和前列腺素E2则可显著降低其摄取。因此，分离的血管灌注大鼠肠道似乎能够区分锌吸收的细胞摄取和细胞到血浆转移阶段。
