Wasserman R H, Smith C A, Brindak M E, De Talamoni N, Fullmer C S, Penniston J T, Kumar R
Department of Physiology, College of Veterinary Medicine, Cornell University, Ithaca, New York.
Gastroenterology. 1992 Mar;102(3):886-94. doi: 10.1016/0016-5085(92)90174-w.
The basolateral membrane of the enterocyte was previously shown to contain an adenosine triphosphate-dependent calcium pump. Using immunological procedures, the localization of the Ca2+ pump in chick intestine, and the effect of dietary variables on the concentration of the pump, were studied. A monoclonal antibody produced against the human erythrocyte calcium pump was shown to cross-react with a chick intestinal Ca2+ pump epitope. The most intense staining of intestinal tissue, as determined immunohistochemically, occurred at the basolateral membrane of the duodenum, jejunum, ileum, and colon, with minor staining elsewhere. By the Western blotting procedure, vitamin D repletion of vitamin D-deficient chicks was shown to significantly increase the concentration of the Ca2+ pump epitope of duodenal, jejunal, and ileal mucosa by a factor of 2-3. Chicks were also fed diets deficient in calcium or phosphorus, a situation known to result in the stimulation of the synthesis of calbindin-D28k and an enhancement of the efficiency of Ca2+ absorption. Adaptation of the chicks to these deficient diets was verified by an increase in intestinal levels of calbindin-D28k, and is now shown to increase the Ca2+ pump epitope. From these immunological studies, it seems apparent that dietary variables that enhance intestinal Ca2+ absorption also increase the amount of the intestinal basolateral Ca2+ pump.
肠上皮细胞的基底外侧膜先前已被证明含有一种依赖三磷酸腺苷的钙泵。运用免疫学方法，研究了钙泵在鸡肠道中的定位，以及饮食变量对该泵浓度的影响。已证明一种针对人红细胞钙泵产生的单克隆抗体与鸡肠道钙泵表位发生交叉反应。通过免疫组织化学测定，肠道组织染色最深的部位出现在十二指肠、空肠、回肠和结肠的基底外侧膜，其他部位染色较浅。通过蛋白质印迹法显示，给维生素D缺乏的雏鸡补充维生素D可使十二指肠、空肠和回肠黏膜的钙泵表位浓度显著增加2至3倍。还给雏鸡喂食钙或磷缺乏的日粮，已知这种情况会刺激钙结合蛋白-D28k的合成并提高钙吸收效率。雏鸡对这些缺乏日粮的适应性通过肠道钙结合蛋白-D28k水平的升高得到验证，并且现在显示也会增加钙泵表位。从这些免疫学研究来看，显然增强肠道钙吸收的饮食变量也会增加肠道基底外侧钙泵的量。
