Borbhuiya M A, Sharma R
Department of Biochemistry, North Eastern Hill University, Shillong, India.
Biochem Mol Biol Int. 1995 Nov;37(4):645-52.
Specific binding of [3H]dexamethasone to its intracellular receptors and the subsequent activation of hormone-receptor complexes were studied in the liver of mice at various postnatal ages. The results indicate that the level (fmol/mg protein) of receptors is significantly higher in the liver of 30-day old mice as compared to other ages studied. Scatchard analysis of binding data exhibits no change in the affinity of hormone to receptor during development. The magnitude of both temperature- and salt-dependent activation of glucocorticoid receptor shows no change in 10- and 60-day old mice, as judged by DNA-cellulose binding. Whereas nuclear binding of temperature activated hormone-receptor complexes is more pronounced in 10-day old mice. Cross-mixing experiments indicate nuclear specificity. DNase I digestion studies showed higher extractability of bound [3H]dexamethasone-receptor complexes from nuclei of 10-day (70%) as compared to 60-day (46%) old mice. These findings indicate changes in the hepatic glucocorticoid receptor level and also in the nature of chromatin organization during development, which might play an important role in the glucocorticoid action mechanism in developing animals.
研究了不同出生后年龄小鼠肝脏中[3H]地塞米松与其细胞内受体的特异性结合以及随后激素-受体复合物的激活情况。结果表明，与其他研究年龄相比，30日龄小鼠肝脏中受体水平（fmol/mg蛋白）显著更高。结合数据的Scatchard分析显示，发育过程中激素与受体的亲和力没有变化。根据DNA-纤维素结合判断，10日龄和60日龄小鼠中糖皮质激素受体的温度和盐依赖性激活程度没有变化。而温度激活的激素-受体复合物的核结合在10日龄小鼠中更为明显。交叉混合实验表明具有核特异性。DNase I消化研究显示，与60日龄（46%）小鼠相比，10日龄（70%）小鼠细胞核中结合的[3H]地塞米松-受体复合物的可提取性更高。这些发现表明，发育过程中肝脏糖皮质激素受体水平以及染色质组织性质发生了变化，这可能在发育中小鼠的糖皮质激素作用机制中发挥重要作用。
