Evidence for a new class of corticosterone receptors in the rat kidney.
Evidence for a new class of corticosterone receptors in the rat kidney.
复制标题
大鼠肾脏中存在一类新型皮质酮受体的证据。
作者：
D. Feldman;J. Funder;I. Edelman
最近的研究已经证明了醛固酮（I型）和糖皮质激素（II型）的高亲和力肾细胞质受体的性质，其以约两倍于皮质酮的亲和力结合地塞米松。我们现在提出的证据表明存在第三类肾细胞质受体（III型），类似但可能不同于血浆皮质类固醇结合球蛋白（CBG）。III型位点对皮质酮具有高亲和力，25 ℃时Kdisg = 3 × 10- 9 M，对醛固酮和地塞米松的亲和力非常低。III型受体与3 H-皮质酮的结合遵循饱和动力学，各种类固醇对这些位点的相对亲和力按以下顺序排列：皮质酮>皮质醇>脱氧皮质酮>孕酮>醛固酮>地塞米松。在肾脏内，内髓质比外皮质显示出更高的III型受体浓度。蛋白质性质的III型R.
Recent studies have documented the properties of high affinity renal cytoplasmic receptors for aldosterone (Type I ), and for glucocorticoids (Type II) which bind dexamethasone with about twice the affinity shown for corticosterone. We now present evidence for the existence of a third class of renal cytoplasmic receptors (Type III) which resemble but are probably distinct from plasma corticosteroid—binding globulin (CBG). The Type III sites have a high affinity for corticosterone, Kdisg = 3 X 10–9M at 25 C, and very low affinities for both aldosterone and dexamethasone. The Type III receptors follow saturation kinetics in the binding of 3H—corticosterone, and the relative affinities of various steroids for these sites is in the following sequence: corticosterone > cortisol > deoxycorticosterone > progesterone > aldosterone > dexamethasone. Within the kidney, the inner medullapapilla showed substantially higher concentrations of Type III receptors than the outer cortex. The protein nature of the type III r...