Kashgarian M, Ardito T, Hirsch D J, Hayslett J P
Am J Physiol. 1987 Jul;253(1 Pt 2):F8-14. doi: 10.1152/ajprenal.1987.253.1.F8.
To investigate the sites of action of aldosterone (Aldo) and chronic potassium loading (high K) and to determine whether dietary K can modulate collecting duct structure independent of Aldo, a morphometric study of the structure of the initial collecting tubule (ICT), the cortical collecting tubule (CCT), the medullary collecting duct in the outer stripe (MCDOS) and the inner stripe (MCDIS), and the papillary collecting duct (PCD) was carried out in a rat model in which plasma levels of Aldo were clamped at basal or physiologically elevated levels and high K could be induced without concomitant hyperaldosteronism. Elevated levels of Aldo increased cell area (Ac) and basolateral membrane surface (BLM) from control values in the ICT, CCT, and MCDOS but not in the MCDIS or PCD. High K with normal physiological levels of Aldo increased BLM in the ICT and CCT without a concomitant change in AC. No response was seen in MCDOS, MCDIS, or PCD. It is concluded that Aldo can modulate principal cell structure in the collecting duct system in segments extending from the ICT through the MCDOS in the rat and that high K independent of Aldo can influence collecting duct structure only in the ICT and CCT.
为了研究醛固酮（Aldo）和慢性钾负荷（高钾）的作用位点，并确定膳食钾是否能独立于醛固酮调节集合管结构，我们在一个大鼠模型中对初始集合小管（ICT）、皮质集合小管（CCT）、外带髓质集合管（MCDOS）、内带髓质集合管（MCDIS）和乳头集合管（PCD）的结构进行了形态计量学研究。在该模型中，醛固酮的血浆水平被钳制在基础水平或生理升高水平，并且可以在不伴有醛固酮增多症的情况下诱导高钾血症。醛固酮水平升高会使ICT、CCT和MCDOS中的细胞面积（Ac）和基底外侧膜表面积（BLM）相对于对照值增加，但在MCDIS或PCD中则不会。生理水平的醛固酮伴随高钾血症会使ICT和CCT中的BLM增加，而AC没有相应变化。在MCDOS、MCDIS或PCD中未观察到反应。结论是，醛固酮可以调节大鼠从ICT到MCDOS节段的集合管系统中主细胞的结构，并且独立于醛固酮的高钾仅能影响ICT和CCT中的集合管结构。
