Apoptosis in the atresia of ovarian follicles

A number of experiments have shown that only few among the follicles which start growing, are ovulable while the rest become atretic. In the regulation of atresia process primarily gonadotropins and steroids participate as well as many other growth factors. Recent studies have demonstrated that apoptosis of granulosa cells is one of the main factors responsible for follicular atresia. It is believed that in programmed granulosa cell death a decisive role is played by secondary messenger signal cells. It was also shown, that apoptosis of granulosa cells can be initiated by disturbances of metabolism cAMP. In the process this will reach to the expression of genes responsible for degenerative changes of a cell leading to its death. The course of apoptosis of granulosa cells is characterized by similar morphological and biochemical changes which accompany apoptosis of other types of cells. These changes constitute one of the processes initiating changes of structural ovarian follicles. Programmed death of granulosa cells is therefore another piece of evidence, that apoptosis is a physiological process regulating tissue regression and reconstruction.