Abstract
The traditional Chinese medicine, Tokishakuyakusan (TS; Dang-Gui-Shao-Yao-San in Chinese), is frequently applied in obstetrics and gynecology departments in Japanese hospitals. The novel neuropeptide, pituitary adenylate cyclase-activating polypeptide (PACAP) that is transiently induced by the gonadotropin surge, plays an important role in the synthesis of estradiol and progesterone in ovarian granulosa cells. Here, we investigated the effect of TS on PACAP in hypophysectomized (HPX) or ovariectomized (OVX) female rats. The weight of the hypothalamus from HPX rats administered with oral TS for one week did not appreciably change. In contrast, TS decreased the weight of the hypothalamus that was increased by ovariectomy. Moreover, TS promoted the expression of PACAP and PACAP type I receptor (PAC1) mRNA and protein in the hypothalamus of HPX and OVX rats. However, bone metabolism that was increased by removing the pituitary or ovaries was not suppressed. These findings suggest that TS promotes the secretion of gonadotropic hormone through the expression of hypothalamic PACAP, PAC1 mRNA and PAC1 protein.
