Active secretion of calcium by adult rat ileum and jejunum in vitro.
Active secretion of calcium by adult rat ileum and jejunum in vitro.
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体外成年大鼠回肠和空肠主动分泌钙。
DOI：
10.1152/ajplegacy.1973.225.2.415
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发表时间：
1973
期刊：
影响因子：
--
通讯作者：
D. V. Kimberg
中科院分区：
文献类型：
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作者：
M. Walling;D. V. Kimberg
方法成年雄性Holtzman大鼠（Holtzman Co.，威斯康星州麦迪逊）除非另有说明，否则使用重量为400 g或更多的材料。如所示，给动物喂食Purina实验室饲料、低钙试验饲料（LCD）或不含维生素D的饲料（分别为试验dz'ets 170120和69280，General Biochemicals，Chagrin福尔斯，俄亥俄州）。给维生素D充足的动物注射20，000 IU维生素D3的0.25ml（Vi Di 3 Hydrosol，A. Wander SA，Berne，Switzerland，在95%乙醇中稀释）。最初，动物禁食过夜，但由于这通常会导致回肠末端充满极粘附的含胆汁内容物，因此使用未禁食动物进行后续实验，这些动物的肠内容物更容易用冰冷的等渗盐水冲洗掉。通过脑震荡处死动物，并迅速取出十二指肠近端3-4 cm、小肠（空肠）中部近端3-4 cm或回肠末端15-20 cm，剥离粘附组织，并沿沿着肠系膜附件打开。将肠切成约1.5-Z cm长的段，将其粘膜侧朝上放置在软木板上，拉伸至刚好低于撕裂点，并以这种方式保持，直到肠片固定在Lucite半室一侧的销上（开口面积为0.49或0.45 cm 2）。然后将第二个Lucite半室夹在组织上，并如前所述（21）安装制剂，两个室的体积为11或15 ml。这种安装方法提供了可再现的组织扩张，并且当以这种方式处理时，1 cm的原位回肠产生2.2-2.4 cm 2的面积。发现成年大鼠小肠的长度在120- 130 cm的范围内。使用25 mM碳酸氢盐或10 mM N-2-羟乙基哌嗪-N ′-2-乙磺酸（HEPES）缓冲系统。当使用碳酸氢盐缓冲系统时，将溶液用5%CO2和95%O2或N2充气。如图所示。使用HEPES缓冲液，100%O2用于充气，并在37 ℃下用0.1N NaOH滴定至pH 7.40。在实验过程中，两种系统的pH值均保持在初始pH值7.4的0.1 pH单位内。碳酸氢盐缓冲溶液具有以下离子组成，以毫摩尔/升计：Na，144; K，4.7; Ca，1.25;和Mg，1.2，除非另有说明; Cl，127; HC 〇 3，25; S 〇 4，1.2，并且不存在无机磷酸盐。
METHODS Adult male Holtzman rats (Holtzman Co., Madison, Wis.) weighing 400 g or more were used unless noted otherwise. Animals were fed either Purina laboratory chow, low-calcium test diet (LCD), or a vitamin D-free diet (test dz’ets 170120 and 69280, respectively, General Biochemicals, Chagrin Falls, Ohio) as indicated. Vitamin D-repleted animals were given an injection of 20,000 IU of vitamin D3 in 0.25 ml (Vi Di 3 Hydrosol, A. Wander SA, Berne, Switzerland, diluted in 95% ethanol) subcutaneously 48 hr before sacrifice. Initially animals were fasted overnight, but because this generally caused the terminal ileum to be filled with extremely adherent bilecontaining contents, subsequent experiments were conducted with unfasted animals whose intestinal contents were more easily rinsed away with ice-cold isotonic saline. The animals were sacrificed by cerebral concussion and either the proximal 3-4 cm of duodenum, the 3-4 cm just proximal to the middle of the small intestine (jejunum), or the terminal 15-20 cm of ileum was rapidly removed, stripped of adherent tissue, and opened along the mesenteric attachment. The intestine was cut into segments approximately 1.5-Z cm long, which were placed mucosal side up on a cork board, stretched to just below the point of tearing, and held in this manner until the sheet of intestine was secured over the pins of one side of a Lucite half-chamber (area of opening either 0.49 or 0.45 cm2). A second Lucite half-chamber was then clamped against the tissue, and the preparation was mounted as previously described (21) with the volume of both compartments being either 11 or 15 ml. This method of mounting provided reproducible tissue distension, and 1 cm of in situ ileum produced an area of 2.2-2.4 cm2 when treated in this manner. The length of the small intestine in adult rats was found to be in the range of 120-l 30 cm.Solutions. Either 25 mM bicarbonate or 10 rnM N-2-hydroxyethyl piperazine-N’-2-ethanesulfonic acid (HEPES) buffer systems were used. When the bicarbonate buffer system was used, solutions were gassed with 5% CO2 and either 95% 02 or N:! as indicated. With HEPES buffer 100% 02 was used for gassing, and it was titrated to a pH of 7.40 at 37 C with 0.1 N NaOH. Both systems maintained the pH within 0.1 pH unit of the initial pH of 7.4 during the course of the experiments. The bicarbonate-buffered solutions had the following ionic composition, in millimoles per liter: Na, 144; K, 4.7; Ca, 1.25; and Mg, 1.2, unless indicated otherwise; Cl, 127; HC03, 25; S04, 1.2, and no inorganic phosphate was present The 10 mM HEPES