Dillmann W H, Silva E, Surks M I, Oppenheimer J H
Acta Endocrinol (Copenh). 1977 Mar;84(3):548-58. doi: 10.1530/acta.0.0840548.
Sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis of the liver cytosol of euthyroid male rats revealed a prominent band (molecular weight, 26 000 daltons), designated Protein II, which was virtually absent in the cytosol of hypothyroid animals. Injection of 500 mug triiodothyronine (T3) per 100 g body weight resulted in a maximal increase in the level of Protein II, reaching 90% of the euthyroidal level 3 days after hormone administration. Concomitant studies with the liver mitochondrial enzyme alpha-glycerophosphate dehydrogenase (alpha-GPD) indicated that this T3 dose also resulted in a maximal enzyme response in this time period. Since we have estimated that 500 mug of T3 will saturate nearly all nuclear T3 binding sites, these results support the concept that the synthesis of both proteins is limited by nuclear binding. Protein II was absent in the liver cytosol of female rats but could be induced in ovariectomized female rats by androgens. Treatment of male rats with oestradiol resulted in disappearance of Protein II. Since administration of testosterone to hypothyroid male rats caused only a minimal increase in the amount of Protein II, the absence of the protein in hypothyroid animals was not due to androgen deficiency. Similarities in the molecular weight and the response to hormonal manipulation of Protein II and of the urinary alpha2uglobulin, previously reported by Roy (1973) raise the possibility that these proteins are the same. The high concentration of Protein II in male rat cytosol and the relative ease in its identification by SDS polyacrylamide gel electrophoresis make it a potentially useful model protein for the study of thyroid hormone action at the cellular level.
对甲状腺功能正常的雄性大鼠肝胞质溶胶进行十二烷基硫酸钠（SDS）聚丙烯酰胺凝胶电泳，结果显示有一条明显的条带（分子量为26000道尔顿），命名为蛋白质II，而甲状腺功能减退动物的胞质溶胶中几乎没有该条带。每100克体重注射500微克三碘甲状腺原氨酸（T3）可使蛋白质II水平最大程度升高，在激素给药后3天达到甲状腺功能正常水平的90%。同时对肝脏线粒体酶α-甘油磷酸脱氢酶（α-GPD）进行的研究表明，该T3剂量在此时间段内也会使该酶产生最大反应。由于我们估计500微克的T3几乎会饱和所有核T3结合位点，这些结果支持了两种蛋白质的合成均受核结合限制的观点。蛋白质II在雌性大鼠的肝胞质溶胶中不存在，但可在去卵巢的雌性大鼠中被雄激素诱导产生。用雌二醇处理雄性大鼠会导致蛋白质II消失。由于给甲状腺功能减退的雄性大鼠注射睾酮只会使蛋白质II的量有极小的增加，所以甲状腺功能减退动物中该蛋白质的缺失并非由于雄激素缺乏。Roy（1973年）之前报道的蛋白质II与尿α2u球蛋白在分子量以及对激素操作的反应方面的相似性，增加了这些蛋白质是相同蛋白质的可能性。雄性大鼠胞质溶胶中蛋白质II的高浓度以及通过SDS聚丙烯酰胺凝胶电泳相对容易对其进行鉴定，使其成为在细胞水平研究甲状腺激素作用的一个潜在有用的模型蛋白。
