Nuclear Progestin Receptors in Human Uterus

摘要: The characteristics and transfer of human uterine progestin receptors from cytosol to nucleus were studied in a cell-free system using [3H]progesterone ([3H]P), [3H]norethindrone ([3H]NET), acetate ([3H]NETA) as receptor tags. Nuclear binding was observed only the presence cytosol. Various prior treatments cytosol, including warming 20 C, increasing salt concentration 150 mM KCl, or dilution protein 3 mg/ml, increased affinity for cell thus, facilitated more translocation. However, there no detectable difference sedimentation value after activation. salt-extractable (400 KCl) nuclear sites [3H]P, [3H]NET, [3H]NETA characterized by distinct commonality their physiochemical properties, indexed coelution during gel chromatography (mol wt, 72,000), similar rates (4.2S), isoelectric profiles (isoelectric pH 5.3--5.6). concentrations specific different 3H-labeled progestins used. general, number higher (3780--4480 molecules/cell) proliferative phase tissues significantly lower (1790--1920 secretory tissues. Furthermore, high (Kd NET, approximately 0.7--0.8 nM; Kd P, 0.9--1.2 NETA, 6.7--7.1 nM). Despite similarities molecular bindings NET NETA could be distinguished that P dissociation (t 1/2 6.3 h; t 5.5 1.2 h). Moreover, unlike did not bind corticosteroid-binding globulin. These observations indicate various mediate action via common receptor, which translocates nucleus. Further, because advantages, conveniently used tag evaluate receptor.