Activin-A differentially regulates steroidogenesis by sheep granulosa cells.
Intra-ovarian factors, such as activin, are implicated in multiple aspects of follicular development in mammalian ovaries. This study was conducted to investigate a possible effect of activin-A on steroidogenesis in sheep granulosa cells in vitro. Sheep granulosa cells were obtained from medium antral follicles and cultured in a chemically defined RPMI -1640. Oestradiol and progesterone production, secreted by the cultured cells, was evaluated by enzyme-linked immunosorbent assay. In order to determine the dose effect of activin-A on steroidogenesis, granulosa cells were cultured in the presence of increasing concentrations of activin-A (0, 0.5, 5 and 50 ng ml(-1)) for 48 hours. The results revealed that activin-A exerts a differential effect on steroidogenesis in granulosa cells in such a way that it significantly (P < 0.05) suppressed progesterone production and enhanced oestradiol production. These results were confirmed by the time effect of activin-A on oestradiol and progesterone production in granulosa cells. In the absence of activin-A treatment, granulosa cells showed enhanced capacity to produce progesterone, but not oestradiol, as the time progressed from 12 to 48 hours. Treatment of sheep granulosa cells with 25 ng ml(-1)activin-A for 12, 24 and 48 hours significantly stimulated oestradiol production but inhibited progesterone production. These results suggest that activin-A is a local regulator of sheep folliculogenesis that might act to support differentiation in granulosa cells and suppress luteinisation.
Shidaifat
F
F
Department of Basic Veterinary Medical Sciences, Faculty of Veterinary Medicine, Jordan University of Science and Technology, Irbid, Jordan. falah@just.edu.jo
Khamas
W
W
Hailat
N
N
D028341:Activins / Q000494:pharmacology* / Q000502:physiology; D000818:Animals; D004958:Estradiol / Q000032:analysis / Q000096:biosynthesis*; D005260:Female; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D028322:Inhibin-beta Subunits / Q000494:pharmacology* / Q000502:physiology; D006080:Ovarian Follicle / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D011374:Progesterone / Q000032:analysis / Q000096:biosynthesis*; D012756:Sheep / Q000502:physiology*
C422405:activin A; D028341:Activins; D011374:Progesterone; D004958:Estradiol; D028322:Inhibin-beta Subunits