Transforming growth factor-beta: its role in ovarian follicle development.
Ovarian follicular growth and differentiation in response to transforming growth factor-beta (TGFB) was investigated using postnatal and immature ovarian models. TGFB ligand and receptor mRNAs were present in the rat ovary 4-12 days after birth and at day 25. In order to assess the impact of TGFB1 on follicle growth and transition from the primordial through to the primary and preantral stages of development, we established organ cultures with 4-day-old rat ovaries. After 10 days in culture with FSH, TGFB1, or a combination of the two, ovarian follicle numbers were counted and an assessment of atresia was undertaken using TUNEL. Preantral follicle numbers declined significantly when treated with the combination of FSH and TGFB1, consistent with our morphological appraisal suggesting an increase in atretic primary and preantral follicles. To investigate the mechanisms behind the actions of TGFB1, we isolated granulosa cells and treated them with FSH and TGFB1. Markers of proliferative, steroidogenic, and apoptotic capacity were measured by real-time PCR. Cyclin D2 mRNA expression by granulosa cells was significantly increased in response to the combination of FSH and TGFB. The expression of forkhead homolog in rhabdomyosarcoma (Foxo1) mRNA by granulosa cells was significantly reduced in the presence of both FSH and TGFB1, individually and in combination regimes. By contrast, the expression of steroidogenic enzymes/proteins was largely unaffected by TGFB1. These data suggest an inhibitory role for TGFB1 (in the presence of FSH) in follicle development and progression.
Rosairo
Davina
D
Prince Henry's Institute of Medical Research, Clayton, Victoria 3168, Australia.
Kuyznierewicz
Ileana
I
Findlay
Jock
J
Drummond
Ann
A
D000818:Animals; D017209:Apoptosis; D056742:Cyclin D2; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D003864:Depression, Chemical; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D008024:Ligands; D009924:Organ Culture Techniques; D006080:Ovarian Follicle / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D010053:Ovary / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053773:Transforming Growth Factor beta1 / Q000378:metabolism / Q000494:pharmacology*
C486197:Ccnd2 protein, rat; D056742:Cyclin D2; D016213:Cyclins; D008024:Ligands; D012333:RNA, Messenger; D018125:Receptors, Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D005640:Follicle Stimulating Hormone