H+ secretion in rabbit mesonephric collecting tubule.
H+ secretion in rabbit mesonephric collecting tubule.
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兔中肾集合管的 H 分泌。
DOI：
10.1152/ajprenal.1994.267.6.f979
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Schwartz,GJ
中科院分区：
文献类型：
--
作者：
Satlin,LM;Yasoshima,K;Schwartz,GJ
中肾，后肾的前体，最终肾，是12- 20日龄兔胎儿的功能排泄器官。它被认为能使尿囊液酸化。为了确定H+是否发生在远端肾元排泄，我们用微量热法和ph敏感荧光染料检测了离体灌注的中肾收集小管。收集小管分泌H+（吸收HCO3-）的速率是成熟后肾外髓收集管（OMCD）的两倍。乌阿拜因不抑制H+分泌（18.5 +/- 2.2 vs. 16.7 +/- 4.0 pmol.min-1 mm-1, n = 7, P = NS），但去除洗浴液中的Cl-可可逆抑制H+分泌（15.1 +/- 2.3 ~ -0.6 +/- 3.7 ~ 15.5 +/- 1.1 pmol.min-1 mm-1, n = 5, P < 0.05）；腹腔应用n -乙基马来酰亚胺（NEM）， H(+)- atp酶抑制剂，也抑制H+分泌（n = 2）。这些结果表明，中肾收集小管中的H+分泌是由类似于OMCD的转运体介导的。为了验证这一假设，我们用6-羧基荧光素（6- cf）双乙酸酯对15-20天胚胎的收集小管进行染色以鉴定插层样细胞，或用2',7'-双（羧乙基）-5(6)-羧基荧光素乙酰氧基甲酯（BCECF-AM）灌注以测定细胞内pH （pHi）。我们发现139 +/- 15个细胞/mm浓缩6-CF或BCECF，与后肾插层细胞表型一致。（摘要删节250字）
The mesonephros, the precursor of the metanephros, the definitive kidney, is the functional excretory organ in the 12- to 20-day-old rabbit fetus. It is believed to acidify allantoic fluid. To determine whether H+ excretion occurs in the distal nephron, we examined isolated perfused mesonephric collecting tubules by microcalorimetry and pH-sensitive fluorescent dyes. Collecting tubules secreted H+ (absorbed HCO3-) at rates twice those observed in the mature outer medullary collecting duct (OMCD) of the metanephric kidney. H+ secretion was not inhibited by ouabain (18.5 +/- 2.2 vs. 16.7 +/- 4.0 pmol.min-1.mm-1; n = 7, P = NS) but was reversibly inhibited by removing Cl- from the bathing solution (15.1 +/- 2.3 to -0.6 +/- 3.7 to 15.5 +/- 1.1 pmol.min-1.mm-1; n = 5, P < 0.05); luminal application of N-ethylmaleimide (NEM), an inhibitor of the H(+)-ATPase, also inhibited H+ secretion (n = 2). These results suggested that H+ secretion in the mesonephric collecting tubule is mediated by transporters similar to those of the OMCD. To test this hypothesis, we stained collecting tubules from 15-20 day embryos with 6-carboxyfluorescein (6-CF) diacetate to identify intercalated-like cells or perfused them with 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM) to measure intracellular pH (pHi). We found that 139 +/- 15 cells/mm concentrated 6-CF or BCECF, consistent with the phenotype of metanephric intercalated cells.(ABSTRACT TRUNCATED AT 250 WORDS)