Endocrinology of the menopause and hormone replacement therapy
A major endocrine function of the human ovary is the production of oestradiol, a hormone essential for the development of the secondary sex characteristics, for normal reproduction, and for the integrity of the cardiovascular, skeletal, and central nervous systems in particular. Oestradiol is a product of the granulosa cells, and hence its secretion is dependent largely on the presence of ovarian follicles. The number of those follicles falls steeply in the last 10 years or so of reproductive life (1), to approach zero at around the time of final menses (Fig. 10.1.2.1). This results in a profound decline in oestradiol production, to levels less than 10% of those observed during reproductive life. The question of whether the consequences of this decline are to be regarded as ‘natural,’ or as giving rise to a pathological state of oestrogen deficiency, is a controversial one. This chapter describes the endocrine changes which take place from the mid-reproductive years through to the postmenopausal years, and addresses the consequences of these changes and their possible prevention.