Regulation of gonadotropin releasing hormone receptor mRNA expression in cultured rat granulosa cells
| Autor: | Yongbin Park, Minseok Cheon, Kyungza Ryu, Kyungyoon Kam |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
endocrine system
medicine.medical_specialty Granulosa cell Diethylstilbestrol Biology Gonadotropin-Releasing Hormone Rats Sprague-Dawley chemistry.chemical_compound Paracrine signalling Internal medicine medicine Animals RNA Messenger Autocrine signalling Cells Cultured Messenger RNA Forskolin Granulosa Cells Reverse Transcriptase Polymerase Chain Reaction General Medicine Rats Endocrinology chemistry Gene Expression Regulation Hormone receptor Female Follicle Stimulating Hormone hormones hormone substitutes and hormone antagonists Gonadotropin-releasing hormone receptor Receptors LHRH medicine.drug |
| Zdroj: | Yonsei medical journal. 42(2) |
| ISSN: | 0513-5796 |
| Popis: | The homologous regulation of pituitary Gonadotropin Releasing Hormone Receptor (GnRH-R) mRNA expression by GnRH has been well demonstrated. However, the regulation of the ovarian GnRH-R is poorly understood. The present study was performed to demonstrate the presence of GnRH transcripts in addition to GnRH-R mRNA and the regulation of GnRH-R mRNA expression in the granulosa cells isolated from small antral follicles. The GnRH and GnRH-R mRNA levels were determined by a competitive reverse transcription-polymerase chain reaction (RT-PCR). The granulosa cells were obtained from immature rats implanted with diethylstilbestrol for 3 days. When GnRH transcript expression was examined in isolated granulosa cells by RT-PCR, the PCR products showed two bands. The larger band contained intronic sequences and the smaller band was a fully processed GnRH gene transcript identical to hypothalamic GnRH. This suggests that authentic GnRH gene transcripts are expressed in ovarian granulosa cells and may act on the granulosa cells in a paracrine or autocrine manner. Since GnRH action in the granulosa cells is mediated by specific GnRH-R, it is of interest to examine whether GnRH-R is synthesized in the granulosa cells. When the granulosa cells were cultured in media only, GnRH-R mRNA levels increased abruptly within 3 h and gradually decreased thereafter during the 24 h culture period. However, GnRH itself did not alter the GnRH-R mRNA expression levels in cultured granulosa cells. Interestingly, treatment with FSH decreased the GnRH-R mRNA levels in a dose-dependent manner. A time-course analysis revealed that the GnRH-R mRNA levels were significantly lower up to 9 h after FSH treatment, and returned to the basal level between 12 h-24 h. Activation of adenylate cyclase with forskolin also decreased the GnRH-R mRNA levels. It is therefore concluded that in the granulosa cells of the small antral follicles GnRH-R mRNA expression was not homologously regulated by GnRH, while FSH may negatively regulate GnRH-R mRNA expression in the granulosa cells possibly through a cAMP-protein kinase A pathway. |
| Databáze: | OpenAIRE |
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