Imai K, Schneider S L, Drury R E, Murphy G P, Sandberg A A
J Urol. 1984 Aug;132(2):367-71. doi: 10.1016/s0022-5347(17)49629-7.
The effect of cationic zinc on the specific binding of the synthetic progestin, promegestone (17 alpha-21-dimethyl-19-nor-pregna-4,9-diene-3,20-dione, R5020), has been investigated in cytosols from human benign hyperplastic prostate. Zinc was analyzed using flameless atomic absorption spectrometry. Progestin specific binding was assayed using sucrose density gradient centrifugation in a vertical tube rotor. The concentration of endogenous zinc in benign hyperplastic prostate cytosols was 0.53 mM +/- 0.26 (range 0.15 mM to 0.88 mM). No significant relationship was observed between zinc concentration in cytosols and the amount of progestin specific binding in the 7-8S peak in sucrose density gradients. Addition of excess zinc to cytosols (1.6 mM) in the presence or absence of monothioglycerol had no effect on the total amount of 7-8S progestin specific binding observed. Removal of free zinc by gel filtration of cytosols on Sephadex G-25 did not change the amount of 7-8S cytosolic receptor binding observed. The addition of the chelating agents, 2,2',2''-tripyridine, 9,10-phenanthroline or EGTA, after the gel filtration step had no apparent effect on the 7-8S progestin specific binding. The anionic chelator, EDTA, inhibited the 7-8S specific binding in a dose dependent manner. However, this inhibition was not reversed by the addition of excess zinc (6 mM) and was observed at very high concentrations of EDTA. This suggests that the effect of EDTA was due to its anionic effect rather than to its effect as a chelator. We conclude that cationic zinc in concentrations up to 2 mM does not change the amount of 7-8S progestin specific receptor binding in cytosols from BPH tissue.
已在人良性增生前列腺的胞质溶胶中研究了阳离子锌对合成孕激素普美孕酮（17α-21-二甲基-19-去甲孕甾-4,9-二烯-3,20-二酮，R5020）特异性结合的影响。使用无火焰原子吸收光谱法分析锌。采用垂直管转子中的蔗糖密度梯度离心法测定孕激素特异性结合。良性增生前列腺胞质溶胶中内源性锌的浓度为0.53 mM±0.26（范围为0.15 mM至0.88 mM）。在蔗糖密度梯度中，未观察到胞质溶胶中锌浓度与7-8S峰中孕激素特异性结合量之间存在显著关系。在有或没有单硫甘油存在的情况下，向胞质溶胶中添加过量锌（1.6 mM）对观察到的7-8S孕激素特异性结合总量没有影响。通过在葡聚糖凝胶G-25上对胞质溶胶进行凝胶过滤去除游离锌，并未改变观察到的7-8S胞质受体结合量。在凝胶过滤步骤之后添加螯合剂2,2',2''-三吡啶、9,10-菲咯啉或乙二醇双乙胺醚，对7-8S孕激素特异性结合没有明显影响。阴离子螯合剂乙二胺四乙酸（EDTA）以剂量依赖性方式抑制7-8S特异性结合。然而，添加过量锌（6 mM）并不能逆转这种抑制作用，并且在非常高浓度的EDTA下才会观察到这种抑制作用。这表明EDTA的作用是由于其阴离子效应而非螯合效应。我们得出结论，浓度高达2 mM的阳离子锌不会改变良性前列腺增生（BPH）组织胞质溶胶中7-8S孕激素特异性受体结合的量。
