The transport of pteroylglutamic acid across the small intestine of the rat.
The transport of pteroylglutamic acid across the small intestine of the rat.
复制标题
蝶酰谷氨酸穿过大鼠小肠的运输。
DOI：
10.1016/0005-2736(70)90059-3
复制
发表时间：
1970
期刊：
影响因子：
--
通讯作者：
J. Blair
中科院分区：
文献类型：
--
作者：
M. Smith;A. J. Matty;J. Blair
1.用外翻囊法研究了[H]-蝶酰谷氨酸的吸收。从距幽门7-70厘米的肠段制备的囊以相似的速率转运翼酰谷氨酸，而从较远的小肠区域制备的囊在这方面的作用较小。2.转运到空肠囊浆膜侧液中的蝶酰谷氨酸主要以未改变的形式存在。3.当囊粘膜侧翼酰谷氨酸在1·10−7-1·10−6M范围内变化时，空肠内存在一个饱和过程。得到该过程的Kt为0.710−6M。当蝶酰谷氨酸最初存在于1·10−7M的粘膜溶液中时，组织相对于粘膜溶液的浓度是浓缩的。4.在没有初始浓度梯度的情况下，在电化学梯度作用下，没有向浆膜侧的转运。5.在囊粘膜侧加入1·10−的6 M蝶酰谷氨酸，葡萄糖可平行刺激蝶酰谷氨酸转运和水转运。在没有葡萄糖的情况下，翼酰谷氨酸的转运是可察觉的。6.在1·10−~6M的浓度范围内，不同pH值的培养液对蝶酰谷氨酸的转运作用不同，其最适pH分别为6.0和7.0。7.结果表明，当浓度为1·10−6M时，蝶酰谷氨酸以被动扩散和溶剂拖曳两种方式随水流转运。
1. The absorption of [3 H] pteroylglutamic acid was studied using the everted sac technique. Sacs prepared from the portion of the gut between 7 and 70 cm from the pylorus transported pteroylglutamic acid at similar rates, but sacs prepared from the more distal region of the small intestine were less effective in this respect. 2. 2. Pteroylglutamic acid transported into the solution on the serosal side of jejunal sacs was present largely in an unaltered form. 3. 3. When the pteroylglutamic acid on the mucosal side of the sac was varied over a range of 1· 10− 7-1· 10− 6 M, a saturatable process was shown to exist in the jejunum. A K t for this process of 0.7· 10− 6 M was obtained. Pteroylglutamic acid was concentrated by the tissues with respect to the mucosal solutions when it was initially present in the mucosal solution at 1· 10− 7 M concentration. 4. 4. With no initial concentration gradient of pteroylglutamic acid, there was no transport to the serosal side against an electrochemical gradient. 5. 5. With a concentration of 1· 10− 6 M pteroylglutamic acid on the mucosal side of the sac, glucose was found to stimulate pteroylglutamic acid transport and water transport in a parallel manner. In the absence of glucose, pteroylglutamic acid transport was appreciable. 6. 6. At 1· 10− 6 M pteroylglutamic acid concentration, transport varied with the pH value of the incubating solutions, the optimum pH for pteroylglutamic acid transport being 6.0 and that for water transport 7.0. 7. 7. It is suggested that pteroylglutamic acid is transported by both passive diffusion and solvent drag with the water flow, when it is initially present on the mucosal side of the sac at 1· 10− 6 M concentration.