Farman N, Pradelles P, Bonvalet J P
Am J Physiol. 1985 Dec;249(6 Pt 2):F923-32. doi: 10.1152/ajprenal.1985.249.6.F923.
High-performance liquid chromatography (HPLC) analysis was performed on tissue extracts from whole kidney cortex (after in vivo injection or in vitro incubation with [3H]-aldosterone ([3H]A], from products bound to aldosterone receptors in cytoplasmic and nuclear fractions, and from the convoluted (PCT) and straight (PR) portion of the proximal tubule and cortical collecting tubule (CCT) isolated by micro-dissection after in vitro incubation with [3H]A (10 and 80 nM). After in vitro incubation of whole tissue, about 10% of the radioactivity corresponded to three groups of metabolites, two polar ones, which eluted earlier than aldosterone, and one less polar, which eluted later than aldosterone. When HPLC analysis was performed on bound products, after removal of free [3H]A, only one group of polar metabolites was detected (about 8% of the radioactivity) in addition to native [3H]A in the cytoplasmic and nuclear fractions. The binding of polar metabolites was nonspecific (nondisplaceable) and did not vary with incubation time and aldosterone concentration. In isolated tubules, in addition to [3H]A, an early peak of polar metabolites, corresponding to that observed in bound fractions, was present in PCT (10%) and in PR and CCT (20-25%). Other metabolites were not found in isolated tubules. We conclude the following: 1) The kidney is able to form at least three groups of aldosterone metabolites in small amounts. 2) Only one of them (more polar) was detected, as a nonspecifically bound product, in cellular fractions containing hormone-receptor complexes after removal of free [3H]A. Other metabolites were removed with free [3H]A. 3) These polar metabolites were found in both mineralocorticoid target segments such as CCT and in classically nontarget segments such as the proximal tubule. 4) The nonspecificity of the binding of polar metabolites and the absence of selective localization along the nephron suggest that they have no major mineralocorticoid action.
采用高效液相色谱（HPLC）分析法，对全肾皮质组织提取物（体内注射或与[³H] - 醛固酮（[³H]A）体外孵育后）、细胞质和细胞核组分中与醛固酮受体结合的产物，以及经微分离得到的近端小管曲部（PCT）和直部（PR）及皮质集合小管（CCT）（与[³H]A（10和80 nM）体外孵育后）进行分析。全组织体外孵育后，约10%的放射性对应于三组代谢产物，两组极性代谢产物，其洗脱时间早于醛固酮，一组极性较小的代谢产物，其洗脱时间晚于醛固酮。对结合产物进行HPLC分析时，去除游离的[³H]A后，在细胞质和细胞核组分中，除了天然的[³H]A外，仅检测到一组极性代谢产物（约占放射性的8%）。极性代谢产物的结合是非特异性的（不可置换），且不随孵育时间和醛固酮浓度而变化。在分离的小管中，除了[³H]A外，PCT（10%）以及PR和CCT（20 - 25%）中存在一个极性代谢产物的早期峰，与结合组分中观察到的情况一致。在分离的小管中未发现其他代谢产物。我们得出以下结论：1）肾脏能够少量形成至少三组醛固酮代谢产物。2）去除游离的[³H]A后，在含有激素 - 受体复合物的细胞组分中，仅检测到其中一种（极性更强）作为非特异性结合产物。其他代谢产物与游离的[³H]A一起被去除。3）这些极性代谢产物在盐皮质激素作用的靶段如CCT以及传统上的非靶段如近端小管中均有发现。4）极性代谢产物结合的非特异性以及在肾单位中缺乏选择性定位表明它们没有主要的盐皮质激素作用。
