piperidines and 2-3-bis(4-hydroxyphenyl)-propionitrile

The net vascular effect of estrogens on the vasculature is still under debate. Here we tested the effects of estradiol- 17β (E2) as well as estrogen-receptor subtype specific and non-specific agonists and antagonists on the expression and eicosanoid production of lipoxygenase (LO) enzymes expressed in culture human umbilical vascular smooth muscle cells (VSMC), the platelet type 12LO and 15LO type 2. E2 increased 12 and 15LO mRNA expression by 2-3 folds and elicited an acute 50% increase 12 and 15 hydroxyeicosatetraenoic acid (HETE) production. Neither estrogen receptor ERα nor ERβ-specific agonists were able to reproduce the induction of LO expression, but E2-induced expression was effectively blocked by ER non-specific and receptor subtype specific antagonists. Because 12 and 15HETE can increase reactive oxygen species in other cell types, we tested the possibility that E2 could raise ROS through LO. Indeed, E2 as well as the LO products 12 and 15HETE increased reactive oxygen species (ROS) in VSMC. E2-dependent and HETE-induced ROS could be blocked by NAD (P) H-oxidase inhibitors and by the ER general antagonist ICI. E2-induced ROS was partially (∼50%) blocked by the LO inhibitor baicalein, but the LO blocker had no effect on 12 or 15HETE- induced ROS formation, thus suggesting that part of E2-dependent ROS generation resulted from E2-induced 12 and 15HETE. Collectively these findings unveil an unrecognized effect of E2 in human VSMC, to induce 12 and 15LO type 2 expression and activity and suggest that E2-dependent ROS formation in VSMC may be partially mediated by the induction of 12 and 15HETE.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Arachidonate 12-Lipoxygenase; Arachidonate 15-Lipoxygenase; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Flavanones; Gene Expression Regulation; Humans; Hydroxyeicosatetraenoic Acids; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; NADPH Oxidases; Nitriles; Phenols; Piperidines; Primary Cell Culture; Propionates; Pyrazoles; Pyrimidines; Raloxifene Hydrochloride; Reactive Oxygen Species; RNA, Messenger; Umbilical Veins

Multiple lines of evidence suggest that the sex steroid hormone 17-β estradiol (E2) plays a protective role in schizophrenia. Systemic E2 enhances prepulse inhibition (PPI) of the acoustic startle reflex, an operational measure of sensorimotor gating known to be impaired in schizophrenia and related disorders. However, the relative contribution of different estrogen-receptor (ER) isoforms in these associations still awaits examination.. The present study explored the effects of ER-α and ER-β stimulation or blockade on PPI and their functional relevance in an amphetamine-induced PPI deficiency model in male mice.. Prior to the assessment of PPI, C57BL/6N male mice were injected with the ER-α agonist 4,4',4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol (PPT), the ER-α antagonist 1,3-bis (4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy) phenol]-1N-pyrozole dihydrochloride (MPP), the ER-β agonist 2,3-bis (4-hydroxyphenyl)-propionitrile (DPN), or the ER-β antagonist 4-[2-phenyl-5,7-bis (trifluoromethyl) pyrazolo [1,5-a] pyrimidin-3-yl] phenol (PHTPP), with or without concomitant amphetamine treatment.. Acute pharmacological stimulation and blockade of ER-α, respectively, led to a dose-dependent increase and decrease in basal PPI. In contrast, acute treatment with preferential ER-β modulators spared PPI under basal conditions. Pretreatment with either ER-α or ER-β agonist was, however, effective in blocking amphetamine-induced PPI disruption.. Our study demonstrates that activation of either ER isoform is capable of modulating dopamine-dependent PPI levels. At the same time, our results suggest that endogenous ER-α signaling may be more relevant than ER-β in the regulation of sensorimotor gating under basal conditions.

Topics: Animals; Estradiol; Estrogen Receptor Modulators; Male; Mice; Mice, Inbred C57BL; Nitriles; Phenols; Piperidines; Prepulse Inhibition; Pyrazoles; Pyrimidines; Signal Transduction

The expression of arginine-vasopressin (AVP) is regulated by estradiol and testosterone (T) in different neuronal populations by mechanisms that are not yet fully understood. Estrogen receptors (ERs) have been shown to participate in the regulation of AVP neurons by estradiol. In addition, there is evidence of the participation of ERβ in the regulation of AVP expression exerted by T via its metabolite 5α-dihydrotestosterone (5α-DHT) and its further conversion in the androgen metabolite and ERβ ligand 3β-diol. In this study we have explored the role of ERs in the regulation exerted by estradiol and T on AVP expression, using the human neuroblastoma cell line SH-SY5Y. Estradiol treatment increased AVP mRNA levels in SH-SY5Y cells in comparison with cells treated with vehicle. The stimulatory effect of estradiol on AVP expression was imitated by the ERα agonist 4,4',4',-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol and blocked by the ER antagonist, ICI 182,780, and the ERα antagonist 1,3-bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy)phenol]-1hpyrazoledihydrochloride. In contrast, the ERβ agonist 2,3-bis(4-hydroxyphenyl)-propionitrile reduced AVP expression, whereas the ERβ antagonist 4-[2-phenyl-5,7-bis(trifluoromethyl) pyrazolo[1,5-a]pyrimidin-3-yl]phenol enhanced the action of estradiol on AVP expression. T increased AVP expression in SH-SY5Y cells by a mechanism that was dependent on aromatase but not on 5α-reductase activity. The T effect was not affected by blocking the androgen receptor, was not imitated by the T metabolite 5α-DHT, and was blocked by the ERα antagonist 1,3-bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy)phenol]-1hpyrazoledihydrochloride. In contrast, 5α-DHT had a similar effect as the ERβ agonists 2,3-bis(4-hydroxyphenyl)-propionitrile and 3β-diol, reducing AVP expression. These findings suggest that estradiol and T regulate AVP expression in SH-SY5Y cells through ERs, exerting a stimulatory action via ERα and an inhibitory action via ERβ.

Topics: Arginine Vasopressin; Cell Line, Tumor; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Female; Fulvestrant; Gene Expression Regulation, Neoplastic; Humans; Neuroblastoma; Nitriles; Phenols; Piperidines; Pyrazoles; Pyrimidines; Reverse Transcriptase Polymerase Chain Reaction; Testosterone

Like other fish species, Mozambique tilapia has three forms of estrogen receptor, ERα, ERβ1, and ERβ2. A primary function of 17β-estradiol (E(2)) in oviparous species is the hepatic induction of the yolk precursor protein, vitellogenin (Vg). To characterize the roles of ERs in Vg production, transactivation assays and an in vivo study were carried out utilizing agonists for mammalian ERα and ERβ, and an antagonist for mammalian ERα, propyl-pyrazole-triol (PPT), diarylpropionitrile (DPN), and methyl-piperidino-pyrazole (MPP), respectively. ERα was more sensitive and responsive to PPT than ERβ1 or ERβ2 in transactivation assays. All ER isoforms indicated equivalent responsiveness to DPN compared with E(2), although sensitivity to DPN was lower. MPP exhibited antagonistic action on transactivation of all ER isoforms and reduced the E(2) effect on Vg and ERα 48h post-injection. DPN increased ERα and Vg expression and plasma Vg post-injection, whereas PPT was without effect; DPN seems to stimulate Vg production through activation of ERα. The ligand binding domain of all tilapia ER forms shares only 60-65% amino acid identity with human ERα and ERβ. This, together with our results, clearly indicates that agonistic or antagonistic characteristics of PPT, DPN and MPP cannot be extrapolated from mammalian to piscine ERs.

Topics: Animals; Cell Line; Cloning, Molecular; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Humans; Male; Nitriles; Phenols; Piperidines; Propionates; Pyrazoles; Receptors, Estrogen; Tilapia; Transcriptional Activation; Vitellogenins

We investigated the effects of the estrogen receptor-alpha (ERalpha) and -beta (ERbeta) in the regulation of leptin, resistin, and adiponectin expression in 3T3-L1 adipocytes. Mature adipocytes were exposed to estradiol (E2), ERalpha agonist (PPT (4,4',4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol)), ERbeta agonist (DPN (2,3-bis(4-Hydroxyphenyl)-propionitrile)), E2 with ERalpha antagonist (MPP (1,3-Bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy)phenol]-1H-pyrazole dihydrochloride)), and E2 with ERbeta antagonist (R,R-THC ((R,R)-5,11-diethyl-5,6,11,12-tetrahydro-2,8-chrysenediol)) at different concentrations. To clarify the expression and regulation of adipokines by ER subtypes, total RNA was extracted from cells and measured using quantitative PCR. Western blot analysis was performed to evaluate the protein expression of adipokines, ERalpha, and ERbeta. The leptin expression was significantly increased in the cells treated with high concentrations (10(-5) and 10(-6) mol/l) of the PPT (P < 0.01, P < 0.05). By contrast, the leptin expression decreased in a dose-dependent manner in the MPP-treated groups (P < 0.05). High concentrations (10(-5) mol/l) of R,R-THC with E2 (10(-7) mol/l) caused a significant increase of the leptin expression (P < 0.01). The leptin mRNA levels were positively correlated with the ERalpha mRNA levels (r = 0.584, P < 0.01) and negatively correlated with the ERbeta mRNA levels (r = -0.236, P = 0.03) in the adipocytes. The ratio of the ERalpha to ERbeta mRNA levels in the adipocytes was significantly associated with leptin mRNA levels (r = 0.454, P < 0.01). ERalpha induced leptin expression and ERbeta inhibited its expression in 3T3-L1 adipocytes. The ratio of the ERalpha-to-ERbeta expression in 3T3-L1 adipocytes may be an important potential regulatory factor in leptin expression.

Topics: 3T3-L1 Cells; Adipocytes; Adiponectin; Animals; Dose-Response Relationship, Drug; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Leptin; Mice; Nitriles; Phenols; Piperidines; Pyrazoles; Regression Analysis; Resistin; RNA, Messenger

The estrogen-dependent process of vitellogenesis is a key function on oviparous fish reproduction and it has been widely used as an indicator of xenoestrogen exposure. The two estrogen receptor (ER) subtypes, ERalpha and ERbeta, are often co-expressed in the liver of fish. The relative contribution of each ER subtype to modulate vitellogenin production by hepatocytes was studied using selected compounds known to preferentially interact with specific ER subtypes: propyl-pyrazole-triol (PPT) an ERalpha selective agonist, methyl-piperidino-pyrazole (MPP) an ERalpha selective antagonist, and diarylpropionitrile (DPN) an ERbeta selective agonist. First, the relative binding affinity of the test compounds to estradiol for rainbow trout hepatic nuclear ER was determined using a competitive ligand binding assay. All the test ligands achieved complete displacement of specific [(3)H]-estradiol binding from the nuclear ER extract. This indicates that the test ligands have the potential to modify the ER function in the rainbow trout liver. Secondly, the ability of the test compounds to induce or inhibit vitellogenin production by primary cultures of rainbow trout hepatocytes was studied. Estradiol and DPN were the only compounds that induced a dose-dependent increase on vitellogenin synthesis. The lack of vitellogenin induction by PPT indicates that ERalpha could not have a role on this reproductive process whereas the ability of DPN to induce vitellogenin production supports the participation of ERbeta. In addition, this hypothesis is reinforced by the results obtained from MPP plus estradiol. On one hand, the absence of suppressive activity of MPP in the estradiol-induced vitellogenin production does not support the participation of ERalpha. On the other hand, once blocked ERalpha with MPP, the only manifestation of agonist activity of estradiol would be achieved via ERbeta. In conclusion, the present results indicate that vitellogenin production is mainly mediated through ERbeta, implying, furthermore that compounds which only exhibit ERalpha selectivity are not detected by vitellogenin bioassay.

Topics: Animals; Binding, Competitive; Biological Assay; Cell Survival; Cells, Cultured; Dose-Response Relationship, Drug; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Fulvestrant; Hepatocytes; Ligands; Nitriles; Oncorhynchus mykiss; Phenols; Piperidines; Propionates; Pyrazoles; Radioligand Assay; Tamoxifen; Vitellogenins