Whalen R E, Olsen K L
Brain Res. 1978 Aug 18;152(1):121-31. doi: 10.1016/0006-8993(78)90138-5.
Gonadal steroids are thought to act by activation of the genome following cytoplasmic binding, translocation of the hormone--receptor complex to the nucleus and chromatin binding at specific acceptor sites. This study examined the kinetics of chromatin binding of estradiol by hypothalamic and cortical cells of adult gonadectomized male and female rats. In both sexes binding was found to be limited to hypothalamic cells. The kinetics of binding differed between the sexes, estradiol being retained less well in males. In females hypothalamic chromatin binding was shown to be of limited capacity and to be competitively inhibited by unlabeled estradiol. Unlabeled testosterone inhibited estradiol binding when administered subcutaneously 3 h before the estradiol, but not by testosterone when administered either intravenously or concurrently with the estradiol. It was suggested that the observed sex difference in hypothalamic chromatin binding might underlie the relative insensitivity of the male to the lordosis-inducing properties of estradiol.
性腺类固醇被认为是通过细胞质结合后激活基因组、激素 - 受体复合物转位至细胞核以及在特定受体位点与染色质结合来发挥作用的。本研究检测了成年去性腺雄性和雌性大鼠下丘脑和皮质细胞中雌二醇与染色质结合的动力学。在两性中，均发现结合仅限于下丘脑细胞。两性之间的结合动力学有所不同，雌二醇在雄性中的保留情况较差。在雌性中，下丘脑染色质结合显示出容量有限，并受到未标记雌二醇的竞争性抑制。在雌二醇给药前3小时皮下注射未标记的睾酮可抑制雌二醇结合，但静脉注射睾酮或与雌二醇同时给药则不会。有人提出，观察到的下丘脑染色质结合的性别差异可能是雄性对雌二醇诱导脊柱前凸特性相对不敏感的基础。
