| Gonadotropin Regulation of Regulator of G Protein Signaling 2 (RGS-2) Expression in the Rat Ovary. |
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Yu Il Lee, Eun Suk Lee, Sun Ae Kim, Mi Young Kim, Moon Kyoung Cho, Sang Young Chun |
1Department of Obstetrics and Gynecology, Chonnam National University Medical School, Gwangju, Korea.
2Hormone Research Center, Gwangju, Korea. |
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| 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. |
| Key Words:
RGS-2; Ovulation; Preovulatory follicle; Gene expression |
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