Previous studies have demonstrated in the rat ovary that XIAP and HIAP-2 were highly expressed in healthy, but not in atretic, follicles. Whereas granulosa cell levels of IAP were high during gonadotropin-induced follicular development, gonadotropin withdrawal decreased granulosa cell IAP content and induced apoptosis. In addition, gonadotropin-induced, NAIP-mediated suppression of ap-optosis in mouse granulosa cells has been suggested to play an important role in the maintenance of oocyte survival during ovarian folliculogenesis. natural asthma treatment
In hen ovarian follicles during follicular development, the highest levels of the inhibitor of T-cell apoptosis (ita) gene mRNA within the granulosa cell layer were found in preovulatory (atresia-resistant) follicles, with significantly lower levels detected in prehierarchical follicles, a stage at which considerable follicular atresia is observed. The above-described patterns of IAP mRNA expression during follicular development are consistent with a potential role for these genes in protecting granulosa cells from apoptosis and, thus, in maintaining follicle viability. However, the physiological roles of IAPs in follicular development and atresia remain unclear
In the present studies, we have tested the hypothesis that XIAP expression is essential for the regulation of granulosa cell fate and follicular development by FSH. To this end, a follicle culture system coupled to an adenoviral gene-ma-nipulation procedure has, to our knowledge for the first time, been established. Using this approach, we have demonstrated that the increase in XIAP expression induced by FSH is critical for the maintenance of normal follicular growth and development.