17-beta-Estradiol standard

Hepatic gluconeogenesis is the main pathway for blood glucose maintenance activated during fasting. Retardation of insulin action, such as in diabetes mellitus, activates gluconeogenesis during the fed state. While the role of progesterone (P4) in diabetes is controversial, the P4 receptor, progesterone receptor membrane component 1 (PGRMC1), is known to stimulate pancreatic insulin secretion. We investigated the role of P4, via hepatic PGRMC1, during gluconeogenesis. The PGRMC1 binding chemical, AG-205, induced PGRMC1 monomer (25 kDa) abundance, and increased PEPCK expression and glucose production in parallel with cyclic AMP (cAMP) induction in Hep3B cells. PGRMC1-mediated cyclic AMP was inhibited by an adenylate cyclase inhibitor (MDL-12,330A). PEPCK suppression in Pgrmc1 KO hepatocyte was not observed after treatment of MDL-12,330A. PGRMC1 knockdown or overexpression systems in Hep3B cells confirmed that PGRMC1 mediates PEPCK expression via phosphorylation of cAMP-response element binding protein (CREB). CREB phosphorylation and PEPCK expression in primary hepatocytes were greater than that in PGRMC1 knock-out hepatocytes. Progesterone increased PGRMC1 expression, which induced cAMP and PEPCK induction and glucose production. In vivo, P4 suppressed gluconeogenesis following plasma insulin induction under normal conditions in a mouse model. However, P4 increased blood glucose via gluconeogenesis in parallel with increases in PGRMC1 and PEPCK expression in mice in both insulin-deficient and insulin-resistant conditions. We conclude that P4 increases hepatic glucose production via PGRMC1, which may exacerbate hyperglycaemia in diabetes where insulin action is limited.

Pregnancy success requires a proper fetal maternal interaction at the establishment of implantation. Leptin has been described as a multitasking cytokine in pregnancy, particularly in the placenta, where it acts as an autocrine hormone. The expression of leptin in normal trophoblastic cells is regulated by different endogenous signals. We have previously reported that 17 beta-estradiol upregulates placental leptin expression through genomic and non-genomic mechanisms. To improve the knowledge of estrogen receptor mechanisms in regulating leptin gene expression, we examined transcription nuclear factor kappa B (NF kappa B) effect on estradiol leptin induction in human BeWo cell line and human term placental explants. We demonstrated that estradiol induction effect on leptin expression is blocked by the inhibition of NF kappa B signaling. We also found that the overexpression of p65 subunit, the active form of NF kappa B, induces leptin expression. Moreover, downregulation of estrogen receptor alpha (ER alpha), through a specific siRNA, abolished kappa B effect on leptin expression. We also demonstrated that ER alpha enhanced NF kappa B signaling pathway activation in trophoblastic cells. Estradiol treatment significantly increased p65 expression and phosphorylation of the inhibitory protein kappa B alpha (I kappa B alpha). A reporter plasmid containing NF kappa B elements was also induced in response to estradiol stimulation. Localization experiments revealed that estradiol treatment induced nuclear localization of overexpressed p65. Moreover, the overexpression of ER alpha produced a complete displacement of p65 protein to the nucleus. Finally, immunoprecipitation experiments showed the presence of a complex containing ER alpha and NF-kappa B. All these evidences suggest a cooperative behavior between ER alpha and NF-kappa B transcription factors to induce leptin transcription.