ATP-induced KaiC hexamerization is necessary for the clock function of KaiC.

Background/Aims: Uterine leiomyomas are the most common gynecological benign tumor and greatly affect reproductive health and well-being. The pathophysiology and epidemiology of fibroids are poorly understood. Obesity and elevated blood pressure have been reported to be predisposing factors. In this study, we investigated whether fibroids are associated with some criteria of the metabolic syndrome. Methods: The case patients were 213 women who underwent hysterectomy or myomectomy for fibroids, and the control subjects were 159 women who underwent operation for benign indications other than fibroids. Preoperative information on body mass index (BMI), blood pressure (BP), serum triglyceride (TG) and fasting plasma glucose (FPG) was obtained from medical records. The patients were classified as overweight if they had a preoperatively measured BMI of ≧24.0, hypertensive if BP was ≧140/90 mm Hg, hypertriglyceridemic if TG was ≧150 mg/dl, and hyperglycemic if FPG was ≧110 mg/dl. Results: BMI, BP, TG and FPG were significantly higher in the case group compared with the control group. In logistic regression analysis, fibroids were statistically significantly associated with being overweight and hypertensive. With the combination of these risk factors, the risk of fibroids increased. Conclusion: Uterine leiomyomas may share pathogenic features with the development of metabolic syndrome.

In order to clarify the mechanism by which excess PRL inhibits gonadotropin release, in vivo and in vitro studies were performed with adult female rats. First, we examined the effect of hyperprolactinemia, produced by implantation of anterior pituitary glands under the kidney capsule, on catecholamine turnover in the medial basal hypothalamus (MBH) and on GnRH concentrations in MBH and hypophyseal portal blood. Rats bearing pituitary transplants exhibited increased turnovers of dopamine (DA) in the MBH, decreased concentrations of GnRH in the MBH and in plasma of hypophyseal portal blood and impaired gonadotropin release from the pituitary gland. Second, we examined the effects of PRL on DA release and of DA on GnRH release from rat hypothalamic cells. We observed that PRL stimulated [³H] DA release, and DA inhibited ionophore-induced GnRH release from dispersed hypothalamic cells. Third, we examined the effect of PRL on estrogen-induced LH release using the in vitro perfusion system. We found that administration of PRL suppressed estrogen-induced LH release by suppressing GnRH release from the hypothalamus. These findings suggest that chronic hyperprolactinemia may increase dopaminergic tone in the MBH that may inhibit GnRH secretion from the MBH and LH release from the pituitary and that these processes may be responsible for disturbances of cyclic hypothalamic pituitary-ovarian activity.

Placenta growth factor (PlGF) is a placental angiogenic factor. Metal-responsive transcription factor (MTF)-1 was reported to take part in the hypoxic induction of PlGF in RAS-transformed mouse fibroblasts. We contrarily showed that PlGF mRNA and protein levels decreased under hypoxia in a choriocarcinoma BeWo cell line derived from trophoblast. In this report, we examined whether hypoxia-dependent regulation of the PlGF gene in these cells also depends on MTF-1. We analyzed the effect of hypoxia on MTF-1 expression, and it was revealed to be decreased. Moreover, MTF-1 small interfering RNA treatment decreased PlGF mRNA level. To investigate the transcription of PlGF under hypoxia, we cloned promoter region of the human PlGF. Promoter deletion analysis suggested that triple repeats of metal-responsive element located between -511 and -468 bp in the promoter are important for the hypoxic regulation of PlGF. Treatment with MTF-1 small interfering RNA resulted in the significant decreased luciferase activity in PlGF reporter constructs. Chromatin immunoprecipitation showed the binding of the MTF-1 protein to the promoter region. We examined MTF-1 immunoreactivity in trophoblasts of term placental tissue from patients with normal pregnancies and preeclampsia, which represents a condition of placental hypoxia. Immunoreactivity of the MTF-1 protein was decreased in placentas from pregnant women with preeclampsia when compared with those from normal pregnant women. Taken together, these findings suggest that MTF-1 is involved in hypoxia-dependent regulation of PlGF in trophoblast-derived cells.

BACKGROUND: Although uterine leiomyomas or fibroids are the most common gynecological benign tumor and greatly affect reproductive health and well-being, the pathophysiology and epidemiology of uterine leiomyomas are poorly understood. Elevated blood pressure has an independent, positive association with risk for clinically detected uterine leiomyoma. Angiotensin II (Ang II) is a key biological peptide in the renin-angiotensin system that regulates blood pressure. METHODS: In this study, we investigated the potential role of Ang II (1 -1000 nM) in the proliferation of rat ELT-3 leiomyoma cells in vitro. RT -PCR and western blot analysis with cell proliferation and DNA transfection assays were performed to determine the mechanism of action of Ang II. RESULTS: Ang II induced ELT-3 leiomyoma cell proliferation (P < 0.01) and the expression of Ang II type 1 receptor (AT 1 R) and AT 2 R mRNA and protein was confirmed. Regarding the intracellular signaling pathway, the Ang II-induced cell proliferation was AT 1 R-, epidermal growth factor receptor-, extracellular-regulated kinase-and protein kinase C-dependent but was not dependent on the AT 2 R or phosphatidylinositol-3 kinase or JAK kinase. The AT 1 R blocker telmisartan, effectively repressed Ang II-induced and estradiol-induced cell proliferation (P < 0.01). AT 1 R, but not AT 2 R, plays a role in Ang II-induced ELT-3 cell proliferation. CONCLUSIONS: These experimental findings in vitro highlight the potential role of Ang II in the proliferation of leiomyoma cells.