We evaluated the signaling pathways involved in regulating vascular endothelial growth factor (VEGF), a potent angiogenic growth factor, in response to natural and synthetic progestins in breast cancer cells. Inhibition of the phosphoinositide-3'-kinase (PI3-kinase) signaling pathway or the specificity protein-1 (SP-1) transcription factor abolished both progesterone- and medroxyprogesterone ac...

PURPOSE In endometrial cancer, loss of progesterone receptors (PR) is associated with more advanced disease. This study aimed to investigate the mechanism of action of progesterone and the loss of its receptors (PRA and PRB) in development of endometrial cancer. EXPERIMENTAL DESIGN A 9600-cDNA microarray analysis was performed to study regulation of gene expression in the human endometrial ca...

Gonadotropin-releasing hormone (GnRH) and its agonists have been known to directly affect steroid hormone production in human granulosa cells. In this study, we examined effects of GnRH on Ca2+ mobilization, protein kinase C activity and steroidogenesis of human granulosa cells. Human granulosa cells were harvested by aspiration of follicles during oocyte retrieval for IVF. Test substances, tha...

Physiological principals underlying synchronization of estrus identified 1) hormones naturally controlling the estrous cycle of cattle, 2) hormones commercially available, 3) mode of action of the hormones commercially available, and 4) when/how they might be used to manage estrus and breeding of beef cattle. The products available are progestogens (melengestrol acetate (MGA) and progesterone d...

The metabolism of progesterone bound to uterine nuclear progesterone receptors was accelerated in vitro by incubation at 25°C for 30min with NADPH generator. The characteristics of progesterone metabolites and receptors were examined by 3H-R5020 exchange assay. Progesterone bound nuclei were prepared from uteri of estradiol-primed progesteronetreated ovariectomized rats. The specific nuclear R5...