» Articles » PMID: 18258681

Ovarian Steroids Stimulate Adenosine Triphosphate-sensitive Potassium (KATP) Channel Subunit Gene Expression and Confer Responsiveness of the Gonadotropin-releasing Hormone Pulse Generator to KATP Channel Modulation

Overview
Journal Endocrinology
Specialty Endocrinology
Date 2008 Feb 9
PMID 18258681
Citations 11
Authors
Affiliations
Soon will be listed here.
Abstract

The ATP-sensitive potassium (K(ATP)) channels couple intracellular metabolism to membrane potential. They are composed of Kir6.x and sulfonylurea receptor (SUR) subunits and are expressed in hypothalamic neurons that project to GnRH neurons. However, their roles in regulating GnRH secretion have not been determined. The present study first tested whether K(ATP) channels regulate pulsatile GnRH secretion, as indirectly reflected by pulsatile LH secretion. Ovariectomized rats received sc capsules containing oil, 17beta-estradiol (E(2)), progesterone (P), or E(2)+P at 24 h before blood sampling. Infusion of the K(ATP) channel blocker tolbutamide into the third ventricle resulted in increased LH pulse frequency in animals treated with E(2)+P but was without effect in all other groups. Coinfusion of tulbutamide and the K(ATP) channel opener diazoxide blocked this effect, whereas diazoxide alone suppressed LH. Effects of steroids on Kir6.2 and SUR1 mRNA expression were then evaluated. After 24hr treatment, E(2)+P produced a modest but significant increase in Kir6.2 expression in the preoptic area (POA), which was reversed by P receptor antagonism with RU486. Neither SUR1 in the POA nor both subunits in the mediobasal hypothalamus were altered by any steroid treatment. After 8 d treatment, Kir6.2 mRNA levels were again enhanced by E(2)+P but to a greater extent in the POA. Our findings demonstrate that 1) blockade of preoptic/hypothalamic K(ATP) channels produces an acceleration of the GnRH pulse generator in a steroid-dependent manner and 2) E(2)+P stimulate Kir6.2 gene expression in the POA. These observations are consistent with the hypothesis that the negative feedback actions of ovarian steroids on the GnRH pulse generator are mediated, in part, by their ability to up-regulate K(ATP) channel subunit expression in the POA.

Citing Articles

Role of potassium channels in female reproductive system.

Kim J, Song K, Xu B, Wang T Obstet Gynecol Sci. 2020; 63(5):565-576.

PMID: 32838485 PMC: 7494774. DOI: 10.5468/ogs.20064.


Targeted Deletion of PTEN in Kisspeptin Cells Results in Brain Region- and Sex-Specific Effects on Kisspeptin Expression and Gonadotropin Release.

Negron A, Yu G, Boehm U, Acosta-Martinez M Int J Mol Sci. 2020; 21(6).

PMID: 32204355 PMC: 7139936. DOI: 10.3390/ijms21062107.


Increased cerebrospinal fluid levels of GABA, testosterone and estradiol in women with polycystic ovary syndrome.

Kawwass J, Sanders K, Loucks T, Rohan L, Berga S Hum Reprod. 2017; 32(7):1450-1456.

PMID: 28453773 PMC: 6251519. DOI: 10.1093/humrep/dex086.


Gonadal steroids differentially modulate the actions of orphanin FQ/nociceptin at a physiologically relevant circuit controlling female sexual receptivity.

Borgquist A, Rivas V, Kachani M, Sinchak K, Wagner E J Neuroendocrinol. 2014; 26(5):329-40.

PMID: 24617903 PMC: 4167875. DOI: 10.1111/jne.12148.


Shift in Kiss1 cell activity requires estrogen receptor α.

Frazao R, Cravo R, Donato Jr J, Ratra D, Clegg D, Elmquist J J Neurosci. 2013; 33(7):2807-20.

PMID: 23407940 PMC: 3713640. DOI: 10.1523/JNEUROSCI.1610-12.2013.


References
1.
Ibrahim N, Bosch M, Smart J, Qiu J, Rubinstein M, Ronnekleiv O . Hypothalamic proopiomelanocortin neurons are glucose responsive and express K(ATP) channels. Endocrinology. 2003; 144(4):1331-40. DOI: 10.1210/en.2002-221033. View

2.
Foecking E, Szabo M, Schwartz N, Levine J . Neuroendocrine consequences of prenatal androgen exposure in the female rat: absence of luteinizing hormone surges, suppression of progesterone receptor gene expression, and acceleration of the gonadotropin-releasing hormone pulse generator. Biol Reprod. 2005; 72(6):1475-83. DOI: 10.1095/biolreprod.105.039800. View

3.
Sprangers S, Piacsek B . Increased suppression of luteinizing hormone secretion by chronic and acute estradiol administration in underfed adult female rats. Biol Reprod. 1988; 39(1):81-7. DOI: 10.1095/biolreprod39.1.81. View

4.
Leadem C, Yagenova S . Effects of specific activation of mu-, delta- and kappa-opioid receptors on the secretion of luteinizing hormone and prolactin in the ovariectomized rat. Neuroendocrinology. 1987; 45(2):109-17. DOI: 10.1159/000124712. View

5.
Catzeflis C, Pierroz D, Rohner-Jeanrenaud F, Rivier J, SIZONENKO P, Aubert M . Neuropeptide Y administered chronically into the lateral ventricle profoundly inhibits both the gonadotropic and the somatotropic axis in intact adult female rats. Endocrinology. 1993; 132(1):224-34. DOI: 10.1210/endo.132.1.8380374. View