Search results for "Estradiol"
showing 10 items of 203 documents
Low estradiol-to-testosterone ratio is associated with oligo-anovulatory cycles and atherogenic lipidic pattern in women with polycystic ovary syndro…
2010
The estradiol-to-testosterone (E2/T) ratio has been investigated in different diseases but few in vivo data are available with regard to its role in women with ovary syndrome (PCOS). The aim of this study was to evaluate the role of the E2/T ratio in the ovulatory function and metabolic pattern in such women.We retrospectively evaluated hyperandrogenemia, clinical hyperandrogenism, ovarian morphology, hypothalamo-hypophyseal axis and metabolic syndrome parameters in a cohort of 202 consecutive women affected by PCOS. An oral glucose tolerance test measured areas under the curve for insulin (AUC(2hIRI)), for glucose (AUC(2hglucose)), and the HOMA-IR and Matsuda index of insulin resistance we…
Estrogen Regulates the Satellite Cell Compartment in Females
2019
SUMMARY Skeletal muscle mass, strength, and regenerative capacity decline with age, with many measures showing a greater deterioration in females around the time estrogen levels decrease at menopause. Here, we show that estrogen deficiency severely compromises the maintenance of muscle stem cells (i.e., satellite cells) as well as impairs self-renewal and differentiation into muscle fibers. Mechanistically, by hormone replacement, use of a selective estrogen-receptor modulator (bazedoxifene), and conditional estrogen receptor knockout, we implicate 17β-estradiol and satellite cell expression of estrogen receptor α and show that estrogen signaling through this receptor is necessary to preven…
Isoflavonoid-based bone-sparing treatments exert a low activity on reproductive organs and on hepatic metabolism of estradiol in ovariectomized rats
2007
International audience; The use of soy isoflavones is a potential alternative to hormone replacement therapy in post-menopausal bone-loss prevention. Nevertheless, phytoestrogens can target other organs and may disrupt cell proliferation, or could modify endogenous steroid hormone metabolism. These mechanisms could be linked to an increased risk of developing cancer. We therefore studied the possible side effects of such treatments in an experimental model of menopause. Forty adult female Wistar rats were ovariectomized and fed with a genistein-, daidzein- or equol-supplemented diet at bone-sparing levels (10 mg/kg BW/day) for 3 months. The estrogenic effects were assessed by histological a…
Inducibility of the avidin gene by progesterone is suppressed during estrogen-induced cytodifferentiation.
1992
Abstract We have studied epithelial differentiation of the chick oviduct as induced by diethylstilbestrol (DES) and 17β-estradiol (E 2 ). The proportion of goblet cells in the oviduct was slightly higher after E 2 than after DES treatment. Also avidin induction by progesterone was stronger following DES than E 2 priming. In the estrogen pretreated oviduct epithelium, avidin expression was induced by progesterone in the surface epithelial cells, protodifferentiated gland cells and tubular gland cells, but not in goblet cells. During prolonged estrogen treatment, however, the inducibility of avidin by progesterone ceased in tubular gland cells but not in surface epithelial cells. The estrogen…
Therapeutic dosages of oral or transdermal estradiol did not modify sCD40L levels in postmenopausal women.
2008
The CD40/CD40L system is considered a crucial modulator of the inflammatory process underlying the progression and complication of atheroma plaques. The soluble fraction of CD40L (sCD40L) is a reliable indicator of the CD40/CD40L system. Our purpose was to investigate whether a therapeutic dose of estradiol, by either the oral or the transdermal route, was associated with changes in circulating levels of sCD40L. Forty-seven women completed a 4-week course of treatment with either oral estradiol valerate (2 mg/day, 20 women) or transdermal estradiol (50 microg/day, 27 women). Serum levels of sCD40L were measured by conventional enzyme-linked immunosorbent assay. Oral, but not transdermal est…
Dietary xenoestrogens differentially impair 3T3-L1 preadipocyte differentiation and persistently affect leptin synthesis
2008
International audience; Recent observations have highlighted adipogenesis alterations under exposure to several xenoestrogens at critical stages, and pointed at their possible involvement in the pathogenesis of obesity. However, it remains unclear whether these effects are mediated by classical estrogen receptor (ER) binding and subsequent transcriptional modulation. The aim of this study was to determine the (anti-)adipogenic impact of apigenin, bisphenol A, genistein and 17β-estradiol at the onset of adipose cell maturation, and to correlate it to their estrogenic potential. In steroid-free conditions, 3T3-L1 preadipocytes were induced to differentiate in the presence of xenoestrogens for…
Hormonal and metabolic adaptation to fasting: effects on the hypothalamic-pituitary-ovarianaxis and reproductive performance of rabbit does
2006
To assess the impact of acute caloric shortage on reproduction, rabbit does were either fed ad libitum (control, AL), or fasted for 24 (STF) or 48 h (LTF) before induction of ovulation with GnRH injection. Blood samples were collected during the last 3 h of fasting, and the following 4 h after GnRH injection, when feed was provided again, to measure plasma concentrations of LH, estradiol-17β, leptin, insulin, T3, corticosterone, glucose, and NEFA. Before re-feeding, plasma leptin, insulin, and T3 concentrations were lower (P ≤ 0.01) in both fasted groups than in controls, but then gradually increased following realimentation to match those of controls. During fasting, corticoster…
The serum level of free testosterone is reduced in amyotrophic lateral sclerosis
2002
Sporadic amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting upper and lower motoneurons. There is an approximately 2:1 higher incidence of ALS in men compared to women, and this has raised the hypothesis of an involvement of sex hormones in the etiopathogenesis of the disorder. In this work, the serum levels of dehydroepiandrosterone sulphate (DHEAS), 17-betaestradiol, free and total testosterone were measured in 35 patients with defined or probable ALS, according to the El-Escorial/WFN revisited criteria, and compared to those obtained from 57 disease controls, matched for age and gender to the ALS group. We found no differences between ALS cases and …
Pregnenolone sulfate, a naturally occurring excitotoxin involved in delayed retinal cell death.
2002
The present study was designed to investigate the neurosteroid pregnenolone sulfate (PS), known for its ability to modulate NMDA receptors and interfere with acute excitotoxicity, in delayed retinal cell death. Three hours after exposure of the isolated and intact retina to a 30-min PS pulse, DNA fragmentation as assessed by genomic DNA gel electrophoresis and a modified in situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method appeared concurrently with an increase in superoxide dismutase (SOD) activity and thiobarbituric acid-reactive substances (TBARS) levels. At 7 h, the increased amount of DNA laddering was accompanied by a higher number of TUN…
ERa dimerization: a key factor for the weak estrogenic activity of an ERa modulator unable to compete with estradiol in binding assays
2016
PMID: 27400858; International audience; AbstractEstrothiazine (ESTZ) is a weak estrogen sharing structural similarities with coumestrol. ESTZ failed to compete with [3H]17β-estradiol ([3H]17β-E2) for binding to the estrogen receptor α (ERα), questioning its ability to interact with the receptor. However, detection by atomic force spectroscopy (AFS) of an ESTZ-induced ERα dimerization has eliminated any remaining doubts. The effect of the compound on the proliferation of ERα-positive and negative breast cancer cells confirmed the requirement of the receptor. The efficiency of ESTZ in MCF-7 cells was weak without any potency to modify the proliferation profile of estradiol and coumestrol. Gro…