Gosden R G, Faddy M J
Department of Physiology, University Medical School, Edinburgh, Scotland, UK.
Exp Gerontol. 1994 May-Aug;29(3-4):265-74. doi: 10.1016/0531-5565(94)90006-x.
The follicular population. Menopause occurs as a consequence of the continuous utilization of a fixed store of primordial follicles leading to almost total depletion at mid-life or sometimes earlier. The great majority of follicles that disappear are lost by atresia rather than by ovulation, and the rate of loss accelerates in the last decade of menstrual life. The numbers of growing follicles at a given age are correlated with those of the primordial stages, but there are always more being recruited than required for a single ovulation each month. The extent to which a dwindling number is responsible for the character of cycles of the menopausal transition remains unclear. Ovarian secretion. While menstrual cycles remain regular, circulating concentrations of estradiol and progesterone are relatively independent of age. On the other hand, serum levels of inhibin are substantially lower in women approaching menopausal age, probably reflecting smaller numbers of growing follicles at the beginning of the cycle. Alleviation of negative feedback on the pituitary gland results in a greater output of follicle-stimulating hormone (FSH), but the effects of chronic superstimulation on the aging ovary are not known. Follicular aging. Aging of long-lived oocytes could affect the developmental potential of the follicle unit as well as compromising the chances of late pregnancy. Another important field of investigation is therefore to determine the balance of responsibility between cumulated damage to molecules by toxins, on the one hand, and the effects of physiological aging and such epiphenomena as the changing hormonal or paracrine environments, on the other.
卵泡群体。绝经是由于固定数量的原始卵泡持续消耗，导致在中年或有时更早几乎完全耗尽所致。绝大多数消失的卵泡是通过闭锁而非排卵丢失的，且在月经周期的最后十年，卵泡丢失率加速。特定年龄的生长卵泡数量与原始阶段的卵泡数量相关，但每月招募的卵泡数量总是多于单次排卵所需数量。卵泡数量减少在多大程度上导致绝经过渡阶段月经周期的特征尚不清楚。卵巢分泌。在月经周期保持规律时，雌二醇和孕酮的循环浓度相对与年龄无关。另一方面，接近绝经年龄的女性血清抑制素水平显著降低，这可能反映了周期开始时生长卵泡数量较少。垂体负反馈的减轻导致促卵泡生成素（FSH）分泌增加，但长期过度刺激对衰老卵巢的影响尚不清楚。卵泡衰老。长寿卵母细胞的衰老可能会影响卵泡单位的发育潜能，并降低晚期妊娠的几率。因此，另一个重要的研究领域是确定一方面毒素对分子累积损伤与另一方面生理衰老以及激素或旁分泌环境变化等附带现象的影响之间的责任平衡。
