Brtko J, Knopp J, DeGroot L J
Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava.
Endocrinol Exp. 1987 Dec;21(4):251-6.
Nuclear acidic protein fraction containing saturable receptors for thyroid hormones was prepared from purified rat liver nuclei by extraction with 0.3 mol l-1 KCl. The inhibitory effect of an increasing ionic strength on the 3,5,3'-triiodothyronine (T3) binding to receptors at pH 8.0 for 2 h and tested up to 2.0 mol l-1 KCl was confirmed. The nuclear receptor-T3 complex was found resistant to the effect of a higher ionic strength up to 1 mol l-1 KCl when subsequently incubated at pH 8.0 for 1 h. In addition, a rapid dissociation of the receptor-T3 complex at alkaline pH in the order of 10.5 greater than 10.0 greater than 9.0 greater than 8.0 was re-examined. The effect of ATP ranging from 0.05 mmol l-1 to 1.0 mmol l-1 on the stability of the receptor-T3 complex at pH 8.0 was also studied. The experiments were conducted in the presence of 25 mmol l-1 Na2HPO4 in order to suppress the effect of the phosphate groups of ATP molecule by inorganic phosphate. The data confirmed that the concentration of ATP starting from 0.05 mmol l-1 may cause the dissociation of nuclear receptor-T3 complex in vitro.
通过用0.3 mol l-1 KCl提取，从纯化的大鼠肝细胞核中制备了含有甲状腺激素饱和受体的核酸性蛋白组分。证实了离子强度增加对pH 8.0下3,5,3'-三碘甲状腺原氨酸（T3）与受体结合2小时的抑制作用，并测试至2.0 mol l-1 KCl。当随后在pH 8.0下孵育1小时时，发现核受体-T3复合物在高达1 mol l-1 KCl的较高离子强度下具有抗性。此外，重新研究了受体-T3复合物在碱性pH下以10.5大于10.0大于9.0大于8.0的顺序快速解离的情况。还研究了0.05 mmol l-1至1.0 mmol l-1的ATP对pH 8.0下受体-T3复合物稳定性的影响。实验在25 mmol l-1 Na2HPO4存在下进行，以抑制无机磷酸对ATP分子磷酸基团的影响。数据证实，从0.05 mmol l-1开始的ATP浓度可能导致体外核受体-T3复合物的解离。
