Different Concentrations Of 17beta-estradiol Research Articles

Gender Differences in Serum and Glucocorticoid Regulated Kinase-1 (SGK-1) Expression during Renal Ischemia/Reperfusion Injury

Several studies reported sexual dimorphism in the signaling mechanisms of renal ischemia/reperfusion (I/R). The anti-apoptotic serum and glucocorticoid-regulated kinase-1 (SGK-1) is up-regulated and has a significant protective role in renal I/R. SGK-1 has several target molecules, and inhibition of the inducible nitric oxide synthase (iNOS) transcription is one of its effector mechanisms. The objective of the present study was to examine if there is a gender-specific expression and activation of SGK-1 during renal I/R injury. In vitro, treatment of HK-2 kidney proximal tubular cells with different concentrations of 17-beta estradiol had no effect, whereas testosterone increased SGK-1 abundance in a dose-dependent manner. In vivo, in a rat model of unilateral renal I/R injury, there was a higher SGK-1 expression and phosphorylation in males 2 and 24 h after ischemia paralleled by reduction in the mRNA expression of iNOS compared to females. Deprivation of testosterone by castration of males resulted in decreased SGK-1 protein level at all time-points and reduced phosphorylation 2 and 24 h after reperfusion. Our results suggest that testosterone up-regulates SGK-1 in the kidney contributing to sexual dimorphisms in the cell signalling machinery. The significance of the testosterone-regulated SGK-1 level and activity in the kidney needs further investigations.

Estradiol inhibits chondrogenic differentiation of mesenchymal stem cells via nonclassic signaling

We undertook this study to examine the effects of estradiol on chondrogenesis of human bone marrow-derived mesenchymal stem cells (MSCs), with consideration of sex-dependent differences in cartilage repair. Bone marrow was obtained from the iliac crest of young men. Density-gradient centrifugation-separated human MSCs proliferated as a monolayer in serum-containing medium. After confluence was achieved, aggregates were created and cultured in a serum-free differentiation medium. We added different concentrations of 17beta-estradiol (E2) with or without the specific estrogen receptor inhibitor ICI 182.780, membrane-impermeable E2-bovine serum albumin (E2-BSA), ICI 182.780 alone, G-1 (an agonist of G protein-coupled receptor 30 [GPR-30]), and G15 (a GPR-30 antagonist). After 21 days, the aggregates were analyzed histologically and immunohistochemically; we quantified synthesized type II collagen, DNA content, sulfated glycosaminoglycan (sGAG) concentrations, and type X collagen and matrix metalloproteinase 13 (MMP-13) expression. The existence of intracellular and membrane-associated E2 receptors was shown at various stages of chondrogenesis. Smaller aggregates and significantly lower type II collagen and sGAG content were detected after treatment with E2 and E2-BSA in a dose-dependent manner. Furthermore, E2 enhanced type X collagen and MMP-13 expression. Compared with estradiol alone, the coincubation of ICI 182.780 with estradiol enhanced suppression of chondrogenesis. Treatment with specific GPR-30 agonists alone (G-1 and ICI 182.780) resulted in a considerable inhibition of chondrogenesis. In addition, we found an enhancement of hypertrophy by G-1. Furthermore, the specific GPR-30 antagonist G15 reversed the GPR-30-mediated inhibition of chondrogenesis and up-regulation of hypertrophic gene expression. The experiments revealed a suppression of chondrogenesis by estradiol via membrane receptors (GPR-30). The study opens new perspectives for influencing chondrogenesis on the basis of classic and nonclassic estradiol signaling.

Effect of Estrogen on the Expression of Cytokines of the Temporomandibular Joint Cartilage Cells of the Mouse

The purpose of this study was to evaluate the effect of estrogen on the synthesis of cytokines of the temporomandibular joint cells. Mandibular condyles of 10 mice were resected. Twenty of these condylar cartilages were removed and placed in organ culture for 24 hours with media containing different concentrations of 17beta-estradiol. The chondroblasts from the mandibular condyles of 3 mice were cultured with different concentrations of 17beta-estradiol the same as above. Cytokine concentrations were measured by ELISA. The expression and concentration of IL-1 beta, IL-6, and IL-8 were increased with increasing concentration of 17beta-estradiol. The expression and concentration of IL-4 and IL-10 were not different from the control and experimental group. These findings suggest that estrogen has the potential to cause temporomandibular joint disease with induction of the proinflammatory cytokines, IL-1 beta, IL-6, and IL-8.

17β-estradiol and progesterone do not influence the production of cytokines from lipopolysaccharide-stimulated monocytes in humans

To test whether 17beta-estradiol or progesterone influence the cytokine productive capacity of lipopolysaccharide (LPS)-stimulated monocytes in humans. Prospective study. Academic research institution. Seven women in the luteal phase of a normal ovarian cycle, 13 oral contraceptive users, 10 men, and 10 postmenopausal women. Blood samples collected from women in the luteal phase and from oral contraceptive users were used to study the in vivo effect of 17beta-estradiol and progesterone on monocyte cytokine production. Blood samples collected from men and postmenopausal women were used for in vitro incubation with 17beta-estradiol and progesterone. The percentage of monocytes producing tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) after in vitro LPS-stimulation was determined. No in vivo relation in the productive capacities of LPS-stimulated monocytes in the luteal phase of the ovarian cycle was found between progesterone and TNF-alpha or IL-1beta; or between 17beta-estradiol and TNF-alpha or IL-1beta. Moreover, the production of TNF-alpha and IL-1beta by LPS-stimulated monocytes did not vary between periods of oral contraceptive use and nonuse. The production of TNF-alpha and IL-1beta by LPS-stimulated monocytes in the blood of men and postmenopausal women in vitro was not influenced by incubation with different concentrations of 17beta-estradiol or progesterone. We could not find evidence for a causal relationship between 17beta-estradiol or progesterone and TNF-alpha- or IL-1beta-production. We conclude that 17beta-estradiol and progesterone do not influence the cytokine-production capacity of LPS-stimulated monocytes in humans.

Reduction of post injury neointima formation due to 17beta-estradiol and phytoestrogen treatment is not influenced by the pure synthetic estrogen receptor antagonist ICI 182,780 in vitro.

Animal and organ culture experiments have shown beneficial inhibitory estrogen effects on post injury neointima development. The purpose of this study was to investigate whether such estrogen effects are influenced by the estrogen receptor antagonist ICI 182,780. Different concentrations of 17beta-estradiol and the phytoestrogens genistein and daidzein were tested. Female New Zealand White rabbits were benumbed. In situ vascular injury of the thoracic and abdominal aorta was performed by a 3F Fogarty catheter. Segments of 5 mm were randomised and held in culture for 21 days. Three test series were performed: 1) control group--20 microM ICI--30 microM ICI--40 microM ICI. 2) control group--20 microM ICI--40 microM 17beta-estradiol--40 microM 17beta-estradiol + 20 microM ICI. 3) control group--20 microM ICI--40 microM daidzein--40 microM daidzein + 20 microM ICI--20 microM genistein--20 microM genistein + 20 microM ICI. After 21 days the neointima-media-ratio was evaluated. 1) Treatment with ICI 182,780 did not reduce neointima formation significantly (p = 0.05). 2) 40 microM 17beta-estradiol alone (p < 0.0001) and in combination with 20 microM ICI (p < 0.0001) reduced neointima formation significantly. 3) 20 microM genistein alone (p = 0.0083) and combined with 20 microM ICI (p = 0.0053) reduced neointima formation significantly. 40 microM daidzein did not have a significant (p = 0.0637) effect. The estrogen receptor antagonist ICI 182,780 did not modulate the inhibitory estrogen effects on post injury neointima formation. These results do not support the idea that such effects are mediated by vascular estrogen receptors.

17-beta estradiol preserves endothelial cell viability in an in vitro model of homocysteine-induced oxidative stress.

High levels of homocysteine (Hcy) accelerate endothelial cell damage by producing hydrogen peroxide (H(2)O(2)). We investigated whether 17-beta estradiol may prevent the accelerated rate of endothelial cell detachment and reduced cell viability in cultured endothelial cells challenged with Hcy. Cultured bovine aortic endothelial cells (BAEC) were incubated for 72-h with either vehicle (alcohol) or different concentrations of 17-beta estradiol (1 nM [1E2] and 10 nM [10E2]) before being challenged with 0.5 mM of Hcy. Cell viability and H(2)O(2) levels were evaluated at 30 min, 1-, 2-, 4-, 8-, and 24-h after adding Hcy. Cell suspensions were frozen in liquid nitrogen and used later for spectrophotometric measurement of intracellular glutathione (GSH) levels. Cell viability 24 h after Hcy administration was significantly lower in vehicle versus 1 nM and 10 nM 17-beta estradiol (44 +/- 5% vs. 70.66 +/- 4%, [p < 0.001] and 79 +/- 5% respectively, [p < 0.001]). H(2)O(2) levels were higher in vehicle (1 +/- 0.05 microM) compared with 1E2 and 10E2 (0.8 +/- 0.1 microM, p = 0.02 and 0.1 +/- 0.05 microM, respectively, p < 0.001), whereas GSH content was increased in 1E1 and 10E2 versus control (27.69 +/- 4.6 nM/10(6) cells and 43.49 +/- 5.5 nM/10(6) cells vs. 13.33 +/- 1.5 nM/10(6) cells, p < 0.001). Bovine aortic endothelial cells treatment with 17-beta estradiol (0, 1, and 10 nM) and 0.1 mmol buthionine sulfoximine, an inhibitor of gamma-glutamylcysteine synthase, abolished the beneficial effects of estradiol alone on cell viability, GSH content, and H2O2 generation. Estradiol prevents Hcy-induced endothelial cell injury by increasing the intracellular content of GSH.