Cimicifuga racemosa Extract for the Treatment of Climacteric Complaints

Abstract

Cimicifuga racemosa (CR) is widely used to treat climacteric complaints. These complaints, particularly hot flushes, are associated with over-activity of GnRH pulse generator in the hypothalamus, which is significantly reduced by E₂. These effects can be ideally studied in ovariectomized (ovx) rats. In the present contribution we show that over-activity of GnRH pulse generator in the rat model is reduced by E₂ and by CR BNO 1055 as reflected in the reduced LH pulse amplitudes. This effect is not mediated by the pituitary because the extract had no effect on LH and TSH secretion but significantly inhibited prolactin release from cultured pituitary cells indicating the presence of dopaminergic compounds. Both, E₂ and CR treatment of ovx rats had profound effects on the expression of ER-alpha and ER-beta genes in the medio-basal hypothalamus and the preoptic area and both the compounds stimulated tyrosine hydroxylase gene expression in the preoptic area. This hypothalamic site is the location of GnRH perikarya. It can, therefore, be concluded that catecholaminergic mechanisms are involved in the modality by which the E₂ and CR inhibit the over-activity of the GnRH pulse generator in ovx rats and in postmenopausal women.