title: Mechanisms of action of transforming growth factor beta on the expression of follicle-stimulating hormone receptor messenger ribonucleic acid levels in rat granulosa cells.
abstract: The present study was undertaken to identify the mechanisms underlying the effect of transforming growth factor (TGF) beta on FSH receptor (FSH-R) in rat granulosa cells. Compared to the control, the treatment of granulosa cells with TGFbeta (10 ng/ml) increased FSH-R mRNA transcripts (5.5 and 2.4 kilobases) in a time-dependent manner, with a maximum increase of approximately 2-fold at 48 h. We then investigated whether the effect of TGFbeta on FSH-R mRNA levels was the result of increased transcription and/or altered mRNA stability. To determine whether the FSH-R 5'-flanking region plays a role in directing FSH-R mRNA expression, the proximal area of the FSH-R 5'-flanking regions were inserted into an expression vector, pGL-Basic, which contains luciferase as the receptor gene, and the resulting plasmids were transiently transfected into rat granulosa cells. The FSH (30 ng/ml) significantly enhanced the activity of 1862 base pairs of the FSH-R 5'-flanking region, but treatment with TGFbeta did not significantly influence the activity induced by FSH. On the other hand, the decay curves for FSH-R mRNA transcript in primary granulosa cells showed a significant increase in half-life after the addition of TGFbeta. Transforming growth factor beta stimulates the expression of follistatin mRNA accumulation in a dose- and time-dependent manner. Treatment with activin produced a substantial increase in FSH-R mRNA level. Concurrent treatment with follistatin neutralized this activin effect on FSH-R mRNA, as reported, although concurrent treatment with follistatin did not affect TGFbeta-induced FSH-R mRNA. Therefore, the profile of the TGFbeta effect on FSH-R mRNA granulosa cells may be caused by the increased stability of FSH-R mRNA and insensitivity to the follistatin.
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, Gunma University, Maebashi, Gunma 371-8511, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Inoue
authors.forename: Kazuto
authors.initials: K
authors.lastname: Nakamura
authors.forename: Kazuko
authors.initials: K
authors.lastname: Abe
authors.forename: Takashi
authors.initials: T
authors.lastname: Hirakawa
authors.forename: Megumi
authors.initials: M
authors.lastname: Tsuchiya
authors.forename: Yuki
authors.initials: Y
authors.lastname: Oomori
authors.forename: Hiroko
authors.initials: H
authors.lastname: Matsuda
authors.forename: Kaoru
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Minegishi
mesh_terms: D024506:5' Flanking Region; D028341:Activins / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D003609:Dactinomycin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D038681:Follistatin / Q000494:pharmacology; D006107:Granulosa Cells / Q000187:drug effects / Q000502:physiology*; D020871:RNA Stability; D012333:RNA, Messenger / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D011962:Receptors, FSH / Q000187:drug effects / Q000235:genetics*; D013997:Time Factors; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
chemical_list: D038681:Follistatin; D012333:RNA, Messenger; D011962:Receptors, FSH; D016212:Transforming Growth Factor beta; D028341:Activins; D003609:Dactinomycin; D005640:Follicle Stimulating Hormone