Mechanism of fluid secretion in isolated shark renal proximal tubules.
Mechanism of fluid secretion in isolated shark renal proximal tubules.
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离体鲨鱼肾近曲小管液体分泌机制。
DOI：
10.1152/ajprenal.1985.249.6.f884
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Beyenbach,KW
中科院分区：
文献类型：
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作者：
Sawyer,DB;Beyenbach,KW
对棘角鲨肾小球近端肾小管进行了研究，通过关闭分离小管的一端，使另一端保持开放，以收集分泌液，以寻找液体分泌的证据。用shark Ringer浸泡小管时，液体分泌率为27.6 +/- 3.9 (SE) pl X min-1 X mm-1（21个小管）。二丁基cAMP刺激体液分泌50% (P < 0.02, n = 14)，速尿抑制体液分泌50% (P < 0.01, n = 6)，代谢抑制剂阻断体液分泌近100%。分泌液对管周液有轻微高渗（P < 0.01, n = 7），但Na、Cl、S、K和Ca浓度与管周液浓度无显著差异（波长色散光谱、电子探针分析）。cAMP对分泌液成分没有影响，在一些小管中cAMP不刺激分泌液分泌。结合先前的数据，我们提出自发的液体分泌是由NaCl的分泌驱动的。然而，发现肾小球肾小管中NaCl和液体分泌的机制，为鱼类肾脏生理中一些以前无法解释的现象提供了新的视角。
Renal proximal tubules from the glomerular Squalus acanthias were studied for evidence of fluid secretion by closing one end of isolated tubules and leaving the other end open so that secreted fluid could be collected. When tubules were bathed in shark Ringer, fluid secretion rate was 27.6 +/- 3.9 (SE) pl X min-1 X mm-1 (21 tubules). Dibutyryl cAMP stimulated fluid secretion 50% (P less than 0.02, n = 14), furosemide inhibited fluid secretion 50% (P less than 0.01, n = 6), and metabolic inhibitors blocked fluid secretion nearly 100%. Secreted fluid was slightly hyperosmotic to peritubular bath (P less than 0.01, n = 7) but Na, Cl, S, K, and Ca concentrations were not significantly different from bath concentrations (wavelength-dispersive spectroscopy, electron probe analysis). cAMP had no effect on secreted fluid composition, and in some tubules cAMP did not stimulate fluid secretion. In conjunction with previous data we propose that spontaneous fluid secretion is driven by secretion of NaCl. However, finding the mechanism of NaCl and fluid secretion in glomerular renal tubules offers new perspectives of some previously inexplicable phenomena in the renal physiology of fish.