ABSTRACT
Normal tissue development includes cell proliferation, differentiation and ‘controlled’ cell death [1]. During the fertile life span of mammals, the function of the gonads are hormonally regulated. Even though proliferation of somatic cells in the ovary and germ cells in the testis plays important roles in normal gonadal development and function, degeneration of gonadal cells results in the depletion of a majority of the potential number of germ cells in both sexes. In the human ovary, two million oocytes are found at birth and 400000 follicles are present at the onset of puberty. However, only 400 follicles could possibly be ovulated during the female reproductive life [2]. At the time of menopause, no follicles or oocytes can be found in the ovary. Therefore, more than 99.9% of follicles, including oocytes, granulosa and theca cells are deleted and this process is an integral part of the normal ovarian function. Indeed, it is the ‘norm’ for a follicle to die rather than to ovulate. The degenerative process by which 99.9% of follicles are irrevocably committed to undergo cell death is termed atresia. Despite its critical role during the recruitment of follicles for ovulation, the mechanisms underlying the onset and progression of atresia remain poorly understood [3].
