Inhibition of minK protein induced K+ channels in Xenopus oocytes by estrogens

被引:29
作者
Waldegger, S
Lang, U
Herzer, T
Suessbrich, H
Binder, K
LeppleWienhues, A
Nagl, U
Paulmichl, M
Franz, HBG
Kiesl, L
Lang, F
Busch, AE
机构
[1] UNIV TUBINGEN, INST PHYSIOL, D-72076 TUBINGEN, GERMANY
[2] UNIV INNSBRUCK, INST PHYSIOL, A-6010 INNSBRUCK, AUSTRIA
[3] UNIV TUBINGEN, DEPT GYNECOL, D-72076 TUBINGEN, GERMANY
关键词
K(+)channel; estrogen; uterus; electrophysiology;
D O I
10.1007/BF00166894
中图分类号
R9 [药学];
学科分类号
1007 ;
摘要
Previously it was shown that minK protein expression in uterus is regulated by estrogen. In the present study, we were interested in putative direct effects of estrogen on minK protein induced K+ currents (I-minK) in Xenopus oocytes. Superfusion with 17-beta-estradiol (1 mu M) resulted in an inhibition of minK-induced currents, but had no appreciable effects on the delayed rectifier and inward rectifier K+ channels Kv1.1 and Kir2.1, respectively. The inhibition of I-minK by 17-beta-estradiol was concentration-dependent, with an IC50 of approximately 0.5 mu M. In the presence of 17-beta-estradiol, the conductance-voltage relationship was shifted to more depolarized potentials. I-minK inhibition occurred also in the presence of the estrogen-receptor antagonist tamoxifen, suggesting that a mechanism independent of estrogen receptors is involved. The synthetic estrogen diethylstilbestrol (DES) also inhibited I-minK but with a lower affinity (IC50 of 4.5 mu M), while cortisol and progesterone had only weak effects on I-minK. In summary, the results indicate that estrogens directly inhibit I-minK.
引用
收藏
页码:698 / 702
页数:5
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