In most species, reproductive senescence can be explained in the same general terms as physiological senescence. In fact, in some species rapid physiological senescence occurs on the completion of reproduction. The programme in @entity1 is unusual in that ovarian function comes to a relatively abrupt halt at 45-50 years of age, when the impact of somatic senescence on most other functions is minimal. Early reproductive senescence has been reported in other species ( @entity831 , macaques and toothed whales) but it is more attenuated and less abrupt. The proximate cause of physiological menopause seems to be oocyte depletion, but less obvious neuroendocrine changes precede or result from the gradual loss of oocytes. This is not surprising as many age-specific processes are controlled by hormones. Hormones provide a way for an animal to co-ordinate the ageing of different tissues. The failure to comprehend completely the reasons for the biological uniqueness of @entity1 makes the study of the more extreme examples of @entity11157 an important exercise. The @entity393 of ovarian function in certain eukaryotic @entity1 highlights the role of those special maintenance and repair systems that must be functional in the selection process for healthy germ cells. The purpose of this article is to indicate selected areas of clinical and basic investigation that may provide clues to the mechanisms of untimely ageing of the @entity1 ovary. Studies of those @entity1 extremes with @entity393 , or extended ovarian function, may provide critical insights into the unique discordance between somatic and reproductive senescence that is characteristic of normal @entity1 .

Selected enquiries into the causation of XXXX .

@entity1 :: ('9606', 'Species') :: ['women', 'human'] @entity393 :: ('MESH:D034381', 'Disease') :: ['premature loss'] @entity11157 :: ('MESH:D016649', 'Disease') :: ['premature ovarian failure'] @entity831 :: ('9598', 'Species') :: ['chimpanzees']
@entity11157 :: (MESH:D016649,Disease) :: ['premature ovarian failure']
