Suyemitsu T, Terayama H
Endocrinology. 1975 Jun;96(6):1499-508. doi: 10.1210/endo-96-6-1499.
The presence of sites specifically binding natural glucocortocoids in plasma membrane (PM) preparations (PM0, density=1.13-1.16; PM1, density=1.16-1.18) from rat liver was elucidated by equilibrium dialysis as well as by centrifugal methods. Equilibrium dialysis showed the presence of binding sites having a higher affinity for [3-H]cortisol (Kd=1.4 times 10- minus 9M at 4C) in PM0, and that of the binding sites having a lower affinity for [3H] cortisol (Kd=1.3 times 10- minus 8M at 4C) in PM1, while centrifugal analysis showed the presence of higher affinity binding sites (Kd=1.5-1.9 times 10- minus 97 at 0 C) in both PM0 and PM1, and also of intermediate affinity binding sites (Kd=4.1 times 10- minus 9M at 0 C) in PM1. The discrepancy in the cortisol binding parameters obtained by the two different methods seems to be due mainly to the lability of some binding sites, especially the PM1. The glucocorticoid-binding sites in the plasma membranes of rat liver appear to have the highest affinity of corticosterone, followed by cortisol and cortisone. A synthetic glucocorticoid [3H]-dexamethasone, did not show any specific binding to the liver plasma membranes. Neither dexamethasone nor nonglucocorticoids such as estradiol given simultaneously affected [3H] cortisol binding to the plasma membranes.
采用平衡透析法和离心法阐明了大鼠肝脏质膜（PM）制剂（PM0，密度=1.13 - 1.16；PM1，密度=1.16 - 1.18）中存在特异性结合天然糖皮质激素的位点。平衡透析显示，PM0中存在对[³H]皮质醇具有较高亲和力的结合位点（4℃时Kd = 1.4×10⁻⁹M），而PM1中存在对[³H]皮质醇具有较低亲和力的结合位点（4℃时Kd = 1.3×10⁻⁸M），同时离心分析表明，PM0和PM1中均存在高亲和力结合位点（0℃时Kd = 1.5 - 1.9×10⁻⁹M），PM1中还存在中等亲和力结合位点（0℃时Kd = 4.1×10⁻⁹M）。两种不同方法获得的皮质醇结合参数存在差异，这似乎主要是由于某些结合位点的不稳定性，尤其是PM1。大鼠肝脏质膜中的糖皮质激素结合位点对皮质酮的亲和力最高，其次是皮质醇和可的松。合成糖皮质激素[³H] - 地塞米松未显示与肝脏质膜有任何特异性结合。同时给予地塞米松或非糖皮质激素如雌二醇均不影响[³H]皮质醇与质膜的结合。
