Nakane H, Nakane Y, Reach G, Corvol P, Menard J
Am J Physiol. 1978 May;234(5):E472-9. doi: 10.1152/ajpendo.1978.234.5.E472.
The renal metabolism and handling of [1,2-3H]aldosterone ([3H]A) was studied using isolated perfused rat kidney under different perfusion conditions. The metabolite production rate (MPR) and the urinary excretion of [3H]A together with its radiometabolites (UV/P3H) were studied. Among the formed metabolites, no acid-labile conjugate of aldosterone (ALC) was detected. The MPR was not altered in studies using nonfiltering kidney, a result that suggests that the majority of metabolites were formed without requirement of the process of glomerular filtration and tubular uptake of the hormone. High perfusion pressure (high PP) resulted in a striking increase in whole metabolic clearance rate of aldosterone (MCR[3H]A) due mostly to an enhanced urinary excretion of intact aldosterone and, to a lesser degree, to a significant increase in MPR. Factors determining the excretion rate of [3H]A and its metabolites were than investigated under administration of diuretics. Mannitol (44 mM) induced a marked increase in urine volume (UV) accompanied by a significant UV/P3H increase. Meanwhile, 0.1 mM furosemide resulted in an increase only in UV, but not in UV/P3H. These results revealed the UV dependence of aldosterone excretion in certain diuretic conditions.
利用离体灌注大鼠肾脏，在不同灌注条件下研究了[1,2-³H]醛固酮（[³H]A）的肾脏代谢及处理过程。研究了代谢产物生成率（MPR）以及[³H]A及其放射性代谢产物的尿排泄情况（UV/P³H）。在所形成的代谢产物中，未检测到醛固酮的酸不稳定结合物（ALC）。在使用无滤过功能肾脏的研究中，MPR未发生改变，这一结果表明，大多数代谢产物的形成并不需要激素的肾小球滤过和肾小管摄取过程。高灌注压（高PP）导致醛固酮的整体代谢清除率（MCR[³H]A）显著增加，这主要是由于完整醛固酮的尿排泄增加，其次是MPR显著升高。随后在给予利尿剂的情况下研究了决定[³H]A及其代谢产物排泄率的因素。甘露醇（44 mM）使尿量（UV）显著增加，同时UV/P³H也显著升高。与此同时，0.1 mM呋塞米仅使UV增加，而未使UV/P³H增加。这些结果揭示了在某些利尿条件下醛固酮排泄对UV的依赖性。
