title: Regulation of nuclear factor-kappaB (NF-kappaB) activity and apoptosis by estradiol in bovine granulosa cells.
abstract: Although atresia of bovine follicles is associated with apoptosis of granulosa cells, the signals initiating this cell death have not been resolved. NF-kappaB has been implicated as an important regulator of genes controlling apoptosis, and previous studies indicate that estradiol may modulate NF-kappaB activation. We hypothesized that estradiol activates NF-kappaB, and thus, inhibits apoptosis in granulosa cells of dominant follicles. Dominant follicles were collected on Days 4, 6, and 8 of the first follicular wave following ovulation and assayed for NF-kappaB activity. Concentrations of estradiol in follicular fluid decreased on Day 6 compared to Day 4 of the wave. NF-kappaB activity in granulosa cells was lower on Day 8 compared to Days 4 and 6. In vitro, NF-kappaB activity and minimal incidence of apoptosis (<4%), as measured by Annexin V and TUNEL assays, were associated with production of estradiol. However, inhibition of NF-kappaB in vitro led to a suppression of apoptosis. These results indicate that follicular NF-kappaB activation is associated with estradiol production. However, whether NF-kappaB is playing a pro- or anti-apoptotic role in granulosa cells of the dominant bovine follicle remains to be elucidated.
authors.affiliation: Department of Physiological Sciences, University of Arizona, Tucson, AZ 85724, USA.
authors.forename: Kelli E
authors.initials: KE
authors.lastname: Valdez
authors.forename: Adele M
authors.initials: AM
authors.lastname: Turzillo
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002417:Cattle; D004789:Enzyme Activation; D004958:Estradiol / Q000096:biosynthesis / Q000502:physiology*; D005260:Female; D006107:Granulosa Cells / Q000502:physiology*; D016328:NF-kappa B / Q000378:metabolism*; D006080:Ovarian Follicle / Q000502:physiology*
chemical_list: D016328:NF-kappa B; D004958:Estradiol