Korean J Reprod Med.  2008 Jun;35(2):111-118.

Gonadotropin Regulation of Regulator of G Protein Signaling 2 (RGS-2) Expression in the Rat Ovary

• Lee YI
• Lee ES
• Kim SA
• Kim MY
• Cho MK
• Chun SY

Abstract

OBJECTIVE
The purpose of the present study was to examine the hormonal regulation of RGS-2 in the rat ovary.
METHODS
Immature rats were injected with 10 IU of PMSG to induce multiple growth of preovulatory follicles and 10 IU of hCG to induce ovulation. Northern blot analysis performed for gene expression and in situ hybridization performed for mRNA localization.
RESULTS
Northern blot analysis revealed that pregnant mare's serum gonadotropin (PMSG) treatment did not affect RGS-2 mRNA levels. In contrast, human chorionic gonadotropin (hCG) treatment of PMSG-primed rats resulted in an increase in RGS-2 expression within 1~3 h. The major cell-types expressing RGS-2 mRNA were oocytes regardless of follicle size. Interestingly, hCG treatment caused the stimulation of RGS-2 gene expression in granulosa cells of preovulatory and growing follicles. In contrast, cell types expressing RGS-2 protein were theca cells regardless of hCG treatment. Like in vivo, treatment of preovulatory granulosa cells with LH in vitro stimulated RGS-2 levels within 1 h. Interestingly, GnRH antagonist II enhanced the stimulatory action of LH.
CONCLUSION
The present study demonstrates the LH/hCG induction of RGS-2 in preovulatory granulosa cells and suggests a role of RGS-2 in Gq protein signaling pathway during ovulation.

Keyword

RGS-2; Ovulation; Preovulatory follicle; Gene expression

MeSH Terms

Animals
Blotting, Northern
Chorionic Gonadotropin
Female
Gene Expression
Gonadotropin-Releasing Hormone
Gonadotropins
Granulosa Cells
GTP-Binding Protein alpha Subunits, Gq-G11
GTP-Binding Proteins
In Situ Hybridization
Oocytes
Ovary
Ovulation
Rats
RNA, Messenger
Theca Cells
Chorionic Gonadotropin
GTP-Binding Protein alpha Subunits, Gq-G11
GTP-Binding Proteins
Gonadotropin-Releasing Hormone
Gonadotropins
RNA, Messenger