Büküşoğlu C, Sarlak F
Department of Anesthesia Research Laboratories, Brigham and Women's Hospital/Harvard Medical School, Boston, MA 02115, USA.
Eur J Pharmacol. 1996 Feb 29;298(1):79-85. doi: 10.1016/0014-2999(95)00772-5.
We have investigated the rapid steroid effects on intracellular calcium ([Ca2+]i levels in a clonal pituitary cell line (GH3). Among the steroids tested only pregnenolone sulfate induced a rapid and transient [Ca2+]i increase within 1 min. The specificity of pregnenolone sulfate-induced [Ca2+]i increase with respect to steroid structure was pronounced. Other steroids (5-40 microM) including pregnenolone, dehydroepiandrosterone, dehydroepiandrosterone sulfate, progesterone, estradiol-17 beta, testosterone, 5 alpha-dihydrotestosterone, 5 alpha-dihydrotestosterone, 5 alpha-dihydroprogesterone, and 3 alpha,5 alpha-tetrahydroprogesterone were found to be ineffective. The [Ca2+]i increase with pregnenolone sulfate (30 microM) was completely abolished in a Ca(2+)-free medium or in the presence of La3+ (0.1 mM) and Co2+ (5 mM). The organic Ca2+ channel blockers methoxyverapamil (100 microM) and nicardipine (5 microM) both showed similar inhibitions (> 73%). The interaction between pregnenolone sulfate and voltage-gated Ca2+ channels (VGCC) was shown by coapplication of pregnenolone sulfate (10 microM) with Bay K 8644 (0.1 mM) or KCl (15 mM). Coapplication of pregnenolone sulfate with KCl increased the [Ca2+]i in an additive manner. However, with the specific agonist Bay K 8644(+/-), the pregnenolone sulfate effect was potentiated in a majority of the cells, suggesting cooperative interaction between the two. The results demonstrate that pregnenolone sulfate induces a rapid Ca2+ influx in GH3 cells. The marked nicardipine block also suggests that most of the Ca2+ influx is mediated through L-type VGCC.
我们研究了类固醇对克隆垂体细胞系（GH3）细胞内钙（[Ca2+]i）水平的快速影响。在所测试的类固醇中，只有硫酸孕烯醇酮能在1分钟内诱导[Ca2+]i快速且短暂地升高。硫酸孕烯醇酮诱导的[Ca2+]i升高在类固醇结构方面具有显著的特异性。发现其他类固醇（5 - 40微摩尔），包括孕烯醇酮、脱氢表雄酮、硫酸脱氢表雄酮、孕酮、雌二醇 - 17β、睾酮、5α - 二氢睾酮、5α - 二氢孕酮和3α,5α - 四氢孕酮均无作用。在无钙培养基中或存在La3+（0.1毫摩尔）和Co2+（5毫摩尔）时，硫酸孕烯醇酮（30微摩尔）诱导的[Ca2+]i升高完全被消除。有机钙通道阻滞剂甲氧基维拉帕米（100微摩尔）和尼卡地平（5微摩尔）均表现出类似的抑制作用（>73%）。硫酸孕烯醇酮与电压门控钙通道（VGCC）之间的相互作用通过将硫酸孕烯醇酮（10微摩尔）与Bay K 8644（0.1毫摩尔）或KCl（15毫摩尔）共同应用得以显示。硫酸孕烯醇酮与KCl共同应用以相加方式增加[Ca2+]i。然而，对于特异性激动剂Bay K 8644（±），硫酸孕烯醇酮的作用在大多数细胞中得到增强，表明两者之间存在协同相互作用。结果表明，硫酸孕烯醇酮在GH3细胞中诱导快速的Ca2+内流。显著的尼卡地平阻断还表明，大部分Ca2+内流是通过L型VGCC介导的。
