[Endocrinology of climacteric and postmenopause]

Climacterium is the transition from a cyclical ovarian function with ovulation to primarily irregularities and ultimately cessation of follicular maturation with its cyclical production of estrogens and progestins. The reason is the decline in follicle count and the decreasing sensitivity of follicles to pituitary gonadotropins. In this transition a phase of elevated androgen action is found in early menopause ultimately in late menopause the ovarian androgen production decreases while the androgen production through the adrenal glands is maintained and especially prohormones which are metabolished peripherally to active androgens and estrogens are produced. In the late menopause also the adrenal androgen production is decreased. This deficiency of estrogens results in processes of deprivation and degeneration which also are dependent on the decreasing growth hormone action according to decreased production and secretion.