The present study is the first to examine the localization of caspase-3 in the rat ovary and the changes in caspase-3 distribution during follicular atresia and luteal regression. buy flovent inhaler
Caspase-3, which plays a central role in the execution of the apoptotic program in cells, exists as a proenzyme that is cleaved and activated in response to a variety of apoptotic stimuli. We have demonstrated that intense cas-pase-3 immunostaining was present in healthy luteal and theca, but not granulosa cells of the rat ovary. However, caspase-3 was evident in granulosa cells of TUNEL-positive follicles after gonadotropin withdrawal, which suggests that this enzyme is up-regulated in these cells as part of the apoptotic process. Previous studies have shown that caspase-3 mRNA levels were reduced in the rat ovary by gonadotropin treatment, which is consistent with our finding of negligible staining for caspase-3 in the granulosa cells of gonadotropin-primed rats. Gonadotropin has been found to be a critical survival factor in follicular development, particularly at the earliest stages of follicle maturation. The present finding suggests that gonadotropin acts as a survival factor, in part, by regulating the expression of caspase-3 in granulosa cells.