Voltage-dependent K+ channel acts as sex steroid sensor in endocrine cells of the human ovary.
Molecular targets of rapid non-genomic steroid actions are not well known compared to those of the classical transcription pathway, but ion channels have recently been identified to be steroid-sensitive. Especially, in the ovary, the very organ producing high amounts of sex steroids, their rapid actions are not well examined. We now identified a yet unknown target for sex steroids, a voltage-dependent K+ channel (Kv4.2) that contributes to a transient outward K+ current (I(A)) in human granulosa cells (GCs). Sex steroid hormones at concentrations typical for the ovary (1 microM) blocked Kv4.2 thereby attenuating I(A) by about 25% within seconds. We also found both Kv4.2 (KCND2) mRNA and protein in endocrine cells of the human and rhesus macaque ovary, emphasizing the physiological relevance of this channel. Therefore, we propose a role as fast-responding steroid sensor for the Kv4.2 channel. The direct regulation of K+ channel activity by sex steroids might represent a yet unknown mechanism of rapid steroid action in close proximity to the site of steroid production in the primate ovary. Our data might also be important for Kv4 channels in the brain and the cardiovascular system where rapid steroid effects are discussed in the context of prevention of cell death.
Kunz
Lars
L
Anatomical Institute, University of Munich, Biedersteiner Str. 29, Munich, Germany. lars.kunz@lrz.uni-muenchen.de
Rämsch
Romi
R
Krieger
Annette
A
Young
Kelly A
KA
Dissen
Gregory A
GA
Stouffer
Richard L
RL
Ojeda
Sergio R
SR
Mayerhofer
Artur
A
D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D004703:Endocrine System / Q000166:cytology*; D005260:Female; D012739:Gonadal Steroid Hormones / Q000378:metabolism*; D006107:Granulosa Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008253:Macaca mulatta; D008969:Molecular Sequence Data; D010053:Ovary / Q000166:cytology* / Q000378:metabolism; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011374:Progesterone / Q000378:metabolism; D051672:Shal Potassium Channels / Q000235:genetics / Q000378:metabolism*
D012739:Gonadal Steroid Hormones; D026902:Potassium Channel Blockers; D051672:Shal Potassium Channels; D011374:Progesterone; D015761:4-Aminopyridine