Contraluminal transport of small aliphatic carboxylates in the proximal tubule of the rat kidney in situ
Contraluminal transport of small aliphatic carboxylates in the proximal tubule of the rat kidney in situ
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DOI：
10.1007/bf00657505
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发表时间：
1986-11
期刊：
影响因子：
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通讯作者：
K. Ullrich;F. Papavassiliou
中科院分区：
文献类型：
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作者：
K. Ullrich;F. Papavassiliou
为了研究水生小分子脂肪酸的逆行转运特性，应用原位停流微灌流技术[12]。通过用4次S接触时间测量相应放射性标记物质对侧浓度的降低，检验了放射性标记物质流入大脑皮层细胞的浓度依赖性。4 S对侧氯乙酸酯、L乳酸、D乳酸、3羟丁酸酯和乙酰乙酸酯的对侧浓度下降幅度在26%~31%之间。浓度为0.1mmoL/L和10mmoL/L的L对0.1 mmoL/11-乳酸的消失率无明显影响，而非特异性阴离子通道阻断剂5-硝基-2-(苯丙氨基)苯甲酸酯对0.1 mmoL/11-乳酸消失率无明显影响，但显著抑制非特异性阴离子通道阻断剂5-硝基-2-(苯丙氨基)苯甲酸酯的消失率(37%)。丙酸摄取的百分比下降幅度较大，在36%~39%之间，但在0.01、0.1、1.0和10 mmoL/L时也没有差异，丙酮酸在0.1 mmoL/L和10 mmoL/L时分别下降20%和31%，芳香族吡津酸的消失率在0.1和10 mmoL/L时分别为38%和34%，烟酸盐分别为42%和22%。10 mmo1/L浓度的吡嗪酸盐和对氨基马尿酸(PAH)可显著抑制烟酸(0.1mmo1/L)的消失。这些数据符合这样的假设，即亲水性小脂肪酸可能通过非特异性阴离子通道[14]通过简单的扩散穿过对生细胞侧，丙酮酸通过二元酸途径以合作的方式通过丙酮酸，而吡津酸以及烟酸盐通过多环芳烃途径。
In order to study the characteristic of contraluminal transport of hydrophylic small fatty acids the in situ stopped flow microperfusion technique [12] has been applied. By measuring with 4 s contact time the decrease in the contraluminal concentration of the respective radiolabelled substances the concentration dependence of the influx into the cortical cells was tested. The 4 s decrease in contraluminal concentration of chloroacetate,l-lactate,d-lactate, 3-hydroxybutyrate and acetoacetate was between 26% and 31%. For each substance the percent decrease was the same, no matter whether it was offered in a concentration of 0.1 or 10 mmol/l. Contraluminal disappearance of 0.1 mmol/ll-lactate was not influenced by 5 mmol/l H2DIDS, probenecid, phloretin, mersalyl or cyanocinnamate, but it was significantly (37%) inhibited by 5-nitro-2-(phenyl-propyl-amino) benzoate, a blocker of the nonspecific anion channel. The percent decrease in propionate uptake was somewhat larger — between 36% and 39% — but again not different at 0.01, 0.1, 1.0 and 10 mmol/l. With pyruvate the contraluminal decrease was 20% at 0.1 mmol/l and 31% at 10 mmol/l. The percent disappearance of the aromatic pyrazinoate was 38% and 34% at 0.1 and 10 mmol/l and for nicotinate 42% and 22%, respectively. The disappearance of nicotinate (0.1 mmol/l) was significantly inhibited by 10 mmol/l pyrazinoate and paraaminohippurate (PAH). The data are in agreement with the hypothesis that the hydrophilic small fatty acids traverse the contraluminal cell side by simple diffusion, possibly via the unspecific anion channel [14], pyruvate via the dicarboxylic acid pathway in a cooperative manner and pyrazinoate, as well as nicotinate, via the PAH pathway.