Pueraria mirifica phytoestrogens improve dyslipidemia in postmenopausal women probably by activating estrogen receptor subtypes.

Impaired lipid metabolism is an important health problem in postmenopausal women with insufficient estrogens, because dyslipidemia is a risk factor for development of atherosclerosis and the incidence of cardiovascular disease markedly increases after menopause. Pueraria mirifica (PM), a Thai herb, has been noticed as a source of phytoestrogens, estrogen-mimicking plant compounds. However, the clinical effects of PM on lipid metabolism and the underlying molecular mechanisms remain undetermined. Therefore, we examined the effects of PM on serum lipid parameters in a randomized, double-blind, placebo-controlled clinical trial. Nineteen postmenopausal women were randomly assigned to receive oral administration of PM powder or placebo. After 2 months of treatment, the PM group showed a significant increase in serum concentrations of high-density lipoprotein (HDL) cholesterol and apolipoprotein (apo) A-1 (34% and 40%, respectively), and a significant decrease in low-density lipoprotein (LDL) cholesterol and apo B (17% and 9%, respectively), compared with baseline measurements. Moreover, significant decreases were observed in the ratios of LDL cholesterol to HDL cholesterol (37%) and apo B to apo A-1 (35%). Next, we determined the effects of PM phytoestrogens on the activation of estrogen receptor (ER)-mediated transactivation by transient expression assays of a reporter gene in cultured cells. Among PM phytoestrogens, miroestrol and coumestrol enhanced both ERalpha- and ERbeta-mediated transactivation, whereas other phytoestrogens, including daidzein and genistein, preferentially enhanced ERbeta-mediated transactivation. In conclusion, PM has a beneficial effect on lipid metabolism in postmenopausal women, which may result from the activation of gene transcription through selective binding of phytoestrogens to ERalpha and ERbeta.

Herbal medicine, Hachimi-jio-gan, and its component cinnamomi cortex activate the peroxisome proliferator-activated receptor alpha in renal cells.

Hachimi-jio-gan is widely used to improve several disorders associated with diabetes, but its mechanism remains poorly understood. In an attempt to clarify the mechanism of Hachimi-jio-gan, we investigated the effects of this herbal medicine and its components in transfection studies of CV1 cells, especially nuclear receptor-mediated actions. One half (0.5) mg/ml of Hachimi-jio-gan activated peroxisome proliferator-activated receptor (PPARalpha), mediating the activation by 3.1-fold on DR1 response elements; however, it did not affect PPARgamma, thyroid hormone receptor, androgen receptor, estrogen receptor or RXR. In addition, this activation was observed in a dose-dependent manner. Next, to determine which components of Hachimi-jio-gan activate PPARalpha-mediated transcription, 8 of its components (rehmanniae radix, orni fructus, dioscoreae rhizoma, alismatis rhizoma, hoelen, moutan cortex, cinnamomi cortex, aconiti) were tested. Only cinnamomi cortex (1.0 mg/ml) increased PPARalpha-mediated transcription by 4.1-fold, and this activation was specific for PPAR alpha, and not for other nuclear receptors. Moreover, this PPARalpha-related activation by cinnamomi cortex is specifically observed in renal cells. Taken together, these findings indicate that Hachimi-jio-gan and cinnamomi cortex may have a pharmacological effect through the target site for PPARalpha.

A novel TRH-PFTAIRE protein kinase 1 pathway in the cerebellum: subtractive hybridization analysis of TRH-deficient mice.

TRH has been reported to possess several neurophysiological actions in the brain. To gain insights into the molecular mechanisms underlying these effects, particularly in the cerebellum, we attempted to clone a cDNA that was regulated by TRH using TRH knockout mice and subtractive cDNA analysis. Over 100 clones obtained by subtractive hybridization analysis between the wild-type and TRH-1-cerebellum were analyzed. Four clones among them were identical and cdc2-related kinase (PFTAIRE protein kinase 1 (PFTK1)) cDNA, which was previously reported to be expressed only in the brain and testis. PFTK1 mRNA levels in the euthyroid TRH-1- cerebellum supplemented with thyroid hormone were significantly decreased compared with those in the wild-type. Induction of PFTK1 mRNA by TRH was also observed in a time- and dose-dependent manner in human medulloblastoma-derived HTB-185 cells that expressed TRH receptor subtype I mRNA. In addition, treatment of 8-Br-cGMP significantly increased PFTK1 mRNA levels, and a specific inhibitor of cGMP production, ODQ, completely blocked TRH-induced expression of PFTK1 mRNA. Furthermore, induction of PFrK1 mRNA by TRH was significantly inhibited by a NOS specific inhibitor, L-NAME, but not by a MEK inhibitor, PD98059 or a calcium channel inhibitor, nimodipine. These findings demonstrated, for the first time, a novel pathway between a neuropeptide and a cell cycle related peptide in the brain, and PFTK1 may be a key regulator for TRH action in t he cerebellum through t he NO-cGMP pathway.