| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Department of Physiology (I.N., H.I., Y.S., M.K.), Nippon Medical School, Tokyo 113-8602, Japan; and Department of Biophysics and Biochemistry (K.U.-T., K.S.), School of Science, University of Tokyo, Tokyo 113-0033, Japan
Address all correspondence and requests for reprints to: Dr. Masakatsu Kato, Department of Physiology, Nippon Medical School, Sendagi 1, Bunkyo, Tokyo 113-8602, Japan. E-mail: mkato{at}nms.ac.jp.
Estrogens play essential roles in the neuroendocrine control of reproduction. In the present study, we focused on the effects of 17β-estradiol (E2) on the K+ currents that regulate neuronal cell excitability and carried out perforated patch-clamp experiments with the GnRH-secreting neuronal cell line GT1-7. We revealed that a 3-d incubation with E2 at physiological concentrations (100 pM to 1 nM) augmented Ca2+-activated K+ [K(Ca)] currents without influencing Ca2+-insensitive voltage-gated K+ currents in GT1-7 cells. Acute application of E2 (1 nM) had no effect on the either type of K+ current. The augmentation was completely blocked by an estrogen receptor (ER) antagonist, ICI-182,780. An ERβ-selective agonist, 2,3-bis(4-hydroxyphenyl)-propionitrile, augmented the K(Ca) currents, although an ER
-selective agonist, 4,4',4''-[4-propyl-(1H)-pyrazole-1,3,5-triyl]tris-phenol, had no effect. Knockdown of ERβ by means of RNA interference blocked the effect of E2 on the K(Ca) currents. Furthermore, semiquantitative RT-PCR analysis revealed that the levels of BK channel subunit mRNAs for
and β4 were significantly increased by incubating cells with 300 pM E2 for 3 d. In conclusion, E2 at physiological concentrations augments K(Ca) currents through ERβ in the GT1-7 GnRH neuronal cell line and increases the expression of the BK channel subunit mRNAs,
and β4.
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Endocrinology | Endocrine Reviews | J. Clin. End. & Metab. |
| Molecular Endocrinology | Recent Prog. Horm. Res. | All Endocrine Journals |