Seleznev Iu M, Shnyra A A
Biokhimiia. 1985 Jan;50(1):17-24.
A mechanism which determines the difference in the ability of deoxycorticosterone (DOC) to inhibit the binding of 3H-triamcinolone acetonide (3H-TA) to glucocorticoid receptors of rat heart and liver cytosols was investigated. DOC was found to strongly inhibit the binding of 3H-TA by heart cytosol, but to exert only a slight inhibitory effect towards the live cytosol binding. This difference was not due to the influence of the enzymes sensitive to molybdate ions, the presence of DOC-degrading enzymes or contamination of liver cytosol by blood serum. The liver cytosol devoid of the glucocorticoid receptor activity by heating was found to contain a factor modifying the "in vitro" interaction of DOC with the heart cytosol glucocorticoid receptors (receptor modifying factor, RMF). This factor is coeluted with the high molecular weight fraction during gel filtration, is precipitated at 50-70% ammonium sulphate saturation, can be absorbed by DEAE-Sephacel from cytosol at pH 7.4 under hypotonic conditions and extracted at about 0.06 M KC1. The sensitivity to proteases and the lack of sensitivity to nucleases point to the proteinic nature of the factor. It was assumed that in terms of the interaction of some steroids with glucocorticoid receptors, the tissue specificity can, at least partly, be explained by the differences in RMF concentration.
研究了一种机制，该机制决定了脱氧皮质酮（DOC）抑制3H-曲安奈德（3H-TA）与大鼠心脏和肝脏胞浆糖皮质激素受体结合能力的差异。发现DOC能强烈抑制心脏胞浆中3H-TA的结合，但对肝脏胞浆结合仅产生轻微抑制作用。这种差异不是由于对钼酸根离子敏感的酶的影响、DOC降解酶的存在或血清对肝脏胞浆的污染。通过加热去除糖皮质激素受体活性的肝脏胞浆被发现含有一种修饰DOC与心脏胞浆糖皮质激素受体“体外”相互作用的因子（受体修饰因子，RMF）。该因子在凝胶过滤过程中与高分子量部分一起被洗脱，在硫酸铵饱和度为50-70%时沉淀，在低渗条件下pH 7.4时可被DEAE-琼脂糖凝胶从胞浆中吸附，并在约0.06 M KCl时提取。对蛋白酶的敏感性和对核酸酶的不敏感性表明该因子具有蛋白质性质。据推测，就某些类固醇与糖皮质激素受体的相互作用而言，组织特异性至少部分可以由RMF浓度的差异来解释。
