Gonadotrophins modulate hormone secretion and steady-state mRNA levels for activin receptors (type I, IIA, IIB) and inhibin co-receptor (betaglycan) in granulosa and theca cells from chicken prehierarchical and preovulatory follicles.
Ovarian follicle development is regulated through endocrine and local mechanisms. Increasing evidence indicates roles for transforming growth factor beta superfamily members, including inhibins and activins. We recently identified divergent expression of mRNAs encoding activin receptors (ActR) and inhibin co-receptor betaglycan in chicken follicles at different stages of maturation. Here, we compare the actions of LH and FSH (0, 1, 10, 100 ng/ml) on levels of mRNA for ActRI, ActRIIA, ActRIIB and betaglycan in chicken granulosa and theca cells (GC and TC) from preovulatory (F1) and prehierarchical (6-8 mm) follicles. The expression of mRNAs for LH-R and FSH-R and production of inhibin A, oestradiol and progesterone were also quantified. FSH decreased ActRIIB and ActRI mRNA levels in 6-8 mm GC, whereas LH increased the mRNA levels. Both LH and FSH enhanced ActRIIA (5- and 8.5-fold) and betaglycan mRNA expression (2- and 3.5-fold) in 6-8 mm GC. In 6-8 mm TC, LH and FSH both increased the betaglycan mRNA level (7- and 3.5-fold respectively) but did not affect ActRI, ActRIIA and ActRIIB transcript levels. In F1 GC, both LH and FSH stimulated ActRI (2- and 2.4-fold), ActRIIB (3.2- and 2.7-fold) and betaglycan (7- and 4-fold) mRNA levels, while ActRIIA mRNA was unaffected. In F1 TC, LH and FSH reduced ActRIIA (35-50%) and increased (4.5- and 7.6-fold) betaglycan mRNA, but had no effect on ActRI and ActRIIB transcript levels. Results support the hypothesis that expression of ActR and betaglycan are differentially regulated by gonadotrophins during follicle maturation in the hen. This may represent an important mechanism for fine-tuning follicle responsiveness to local and systemic activins and inhibins.
Lovell
Tristan M
TM
School of Biological Sciences, University of Reading, Whiteknights, Reading, Berkshire RG6 6AJ, UK.
Al-Musawi
Sara L
SL
Gladwell
Richard T
RT
Knight
Philip G
PG
D029404:Activin Receptors / Q000235:genetics*; D030201:Activin Receptors, Type I / Q000235:genetics; D030301:Activin Receptors, Type II / Q000235:genetics; D000818:Animals; D002478:Cells, Cultured; D002645:Chickens / Q000378:metabolism*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D006065:Gonadotropins, Pituitary / Q000494:pharmacology*; D006107:Granulosa Cells / Q000378:metabolism; D007118:Immunoassay; D007986:Luteinizing Hormone / Q000494:pharmacology; D006080:Ovarian Follicle / Q000502:physiology*; D016133:Polymerase Chain Reaction / Q000379:methods; D011509:Proteoglycans / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism*; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics*; D013268:Stimulation, Chemical; D013799:Theca Cells / Q000378:metabolism
D006065:Gonadotropins, Pituitary; D011509:Proteoglycans; D012333:RNA, Messenger; D018125:Receptors, Transforming Growth Factor beta; C071736:betaglycan; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D029404:Activin Receptors; D030201:Activin Receptors, Type I; D030301:Activin Receptors, Type II