Treatment of Menopausal Symptoms with Extracts of Cimicifuga Racemosa: In vivo and in vitro Evidence for Estrogenic Activity

Abstract

Menstrual bleeding is the apparent sign of ovarian function during the reproductive phase of a woman. The timepoint of cessation of regularly occurring menstrual cycles is called “menopause”. The activity of the ovary is governed by a complex neuroendocrine circuit which includes the hypothalamus, the pituitary and the ovary. This regulatory circuit ensures the growth of the ovarian follicle harboring the oocyte, its rupture and the formation of the corpus luteum [for review see 13]. The steroidogenic cells of the ovarian follicle secrete estradiol. After ovulation the follicle is transformed into the corpus luteum which now produces, in addition to estradiol, the progestin progesterone. The growth of the ovarian follicle and the formation of the corpus luteum as well as the endocrine activity of the ovary are controled by the pituitary hormones luteinizing hormone (LH) and follicle stimulating hormone (FSH). The release of the gonadotropic hormones LH and FSH is controlled by the peptide gonadotropin releasing hormone (GnRH) which is produced in specialized neurons located in the hypothalamus. Ovarian steroids, in particular estradiol, exert a negative influence on the release of GnRH from the hypothalamus and the secretion of the gonadotropins LH and FSH from the pituitary.