Claire M, Oblin M E, Steimer J L, Nakane H, Misumi J, Michaud A, Corvol P
J Biol Chem. 1981 Jan 10;256(1):142-7.
Adrenalectomized rat kidney is commonly used for the study of mineralocorticoid mechanism of action in mammals. In this model, aldosterone is known to bind to two classes of binding sites: type I (mineralocorticoid) and type II (glucocorticoid). The study of the aldosterone binding in normal rat kidney requires the elimination of endogenous hormones bound to each type of receptor. Thus, a suitable technique was developed using in situ perfusion of the kidneys. The efficacy of this method was of about 85 to 90% at the level of both cytoplasm and nucleus. Aldosterone binding capacity was checked in normal rat kidney after in situ perfusion and was found to be 300 to 500% lower than in adrenalectomized rat kidney, both in cytoplasm and nuclei. Computer analysis of aldosterone binding parameters in the cytoplasm (30,000 X g supernatant) of rat kidney suggested that adrenalectomy might induce an important rise in the number of mineralocorticoid receptors (congruent to 260%). An increase in the number of glucocorticoid receptors was also observed but appeared to be lower. Aldosterone, when perfused during 24 h in adrenalectomized rats, lowered the number of type I sites to the same level as observed in normal rat kidney. This effect was fully reversible after interruption of aldosterone perfusion. These results suggested an aldosterone-induced down regulation of mineralocorticoid receptors.
肾上腺切除大鼠的肾脏常用于研究哺乳动物中盐皮质激素的作用机制。在这个模型中，已知醛固酮可与两类结合位点结合：I型（盐皮质激素）和II型（糖皮质激素）。研究正常大鼠肾脏中的醛固酮结合需要消除与每种受体结合的内源性激素。因此，开发了一种使用肾脏原位灌注的合适技术。该方法在细胞质和细胞核水平的效率约为85%至90%。在原位灌注后检查正常大鼠肾脏中的醛固酮结合能力，发现其在细胞质和细胞核中的水平均比肾上腺切除大鼠肾脏低300%至500%。对大鼠肾脏细胞质（30,000×g上清液）中醛固酮结合参数的计算机分析表明，肾上腺切除可能会导致盐皮质激素受体数量显著增加（约260%）。还观察到糖皮质激素受体数量增加，但似乎较少。在肾上腺切除大鼠中灌注24小时醛固酮后，I型位点的数量降至与正常大鼠肾脏中观察到的相同水平。在醛固酮灌注中断后，这种效应完全可逆。这些结果表明醛固酮可诱导盐皮质激素受体的下调。
