Search results for "estrogens"

Interactive effects of zearalenone and its metabolites on cytotoxicity and metabolization in ovarian CHO-K1 cells.

2014

Zearalenone (ZEA) is a non-steroidal estrogen mycotoxin with high binding affinity to estrogen receptors. ZEA is rapidly absorbed and metabolized in vivo to α-zearalenol (α-ZOL) and β-zearalenol (β-ZOL). So, mixtures of them may be present in biological systems and suppose a hazard to animals and human health. The aims of this study were to determine the cytotoxic effects of ZEA and its metabolites, alone and in combination in ovarian (CHO-K1) cells during 24, 48 and 72h by the MTT assay; and to investigate the metabolism of the CHO-K1 cells on ZEA, and its conversion into α-ZOL and β-ZOL by CHO-K1 cell after 24 and 48h of exposure. The IC50 value obtained for individual mycotoxins range fr…

Review on the toxicity, occurrence, metabolism, detoxification, regulations and intake of zearalenone: An oestrogenic mycotoxin

2005

Zearalenone (ZEA) is a mycotoxin produced mainly by fungi belonging to the genus Fusarium in foods and feeds. It is frequently implicated in reproductive disorders of farm animals and occasionally in hyperoestrogenic syndromes in humans. There is evidence that ZEA and its metabolites possess oestrogenic activity in pigs, cattle and sheep. However, ZEA is of a relatively low acute toxicity after oral or interperitoneal administration in mice, rat and pig. The biotransformation for ZEA in animals involves the formation of two metabolites alpha-zearalenol (alpha-ZEA) and beta-zearalenol (beta-ZEA) which are subsequently conjugated with glucuronic acid. Moreover, ZEA has also been shown to be h…

Phytoestrogens increase the capacity of serum to stimulate prostacyclin release in human endothelial cells

2003

Both the estrogen receptor (ER) alpha and beta isoforms are expressed in the endothelium. The ER beta has been assigned a crucial role in normal vascular wall function. Prostacyclin has been ascribed a beneficial effect on vessel wall physiology. Isoflavones bind with higher affinity to ER beta. We investigated the hypothesis that their administration to postmenopausal women can promote endothelial prostacyclin production.Twenty-five healthy postmenopausal women with mild climacteric symptoms received capsules containing 55 mg/day isoflavones derived from soy and red clover for 6 months. Cultured human umbilical vein endothelial cells (HUVECs) were exposed for 24 h to serum collected before…

Fostering antioxidant defences: up-regulation of antioxidant genes or antioxidant supplementation?

2007

Vitamins have traditionally been considered as food components that are required in the normal diet to prevent deficiencies. However, a newer concept of the function of vitamins in nutrition has taken them beyond simply prevention of deficiency symptoms. This concept considers that many vitamins, when taken in relatively larges doses, have important functions beyond preventing deficiencies. Linus Pauling was instrumental in putting forward this concept, particularly for vitamin C. Thus, relatively high intakes of vitamins, and in particular vitamins C and E which are antioxidants, are considered to be healthy for the human population. This may be true in some special situations such as, for…

Abnormal peripubertal development of the rat mammary gland following exposure in utero and during lactation to a mixture of genistein and the food co…

2011

The impact of early exposure to endocrine disruptor mixtures on mammary gland development is poorly known. Here, we identify the effects of a conception to weaning exposure of rats to the phytoestrogen genistein (G) and/or the antiandrogen vinclozolin (V) at 1 mg/kg-d, alone or in association. Using several approaches, we found that G- and GV-exposed rats displayed significantly greater epithelial branching and proliferation, wider terminal end buds than controls at PND35, as well as ductal hyperplasia and periductal fibrosis. Focal branching defects were present in V-exposed rats. An increased ER and AR expression was observed in G- and CV- as compared to V-exposed rats at PND35. Surprisin…

Molecular Basis for Endocrine Disruption by Pesticides Targeting Aromatase and Estrogen Receptor

2020

The intensive use of pesticides has led to their increasing presence in water, soil, and agricultural products. Mounting evidence indicates that some pesticides may be endocrine disrupting chemicals (EDCs), being therefore harmful for the human health and the environment. In this study, three pesticides, glyphosate, thiacloprid, and imidacloprid, were tested for their ability to interfere with estrogen biosynthesis and/or signaling, to evaluate their potential action as EDCs. Among the tested compounds, only glyphosate inhibited aromatase activity (up to 30%) via a non-competitive inhibition or a mixed inhibition mechanism depending on the concentration applied. Then, the ability of the thr…

Comment on "Effects of Elastic Resistance Band Exercise on Postural Balance, Estrogen, Bone Metabolism Index, and Muscle Strength of Perimenopausal P…

2017

Estrogens and Stem Cells in Thyroid Cancer

2014

Recent discoveries highlight the emerging role of estrogens in the initiation and progression of different malignancies through their interaction with stem cell compartment. Estrogens play a relevant role especially for those tumors bearing a gender disparity in incidence and aggressiveness, as occurs for most thyroid diseases. Although several experimental lines suggest that estrogens promote thyroid cell proliferation and invasion, their precise contribution in stem cell compartment still remains unclear. This review underlines the interplay between hormones and thyroid function, which could help to complete the puzzle of gender discrepancy in thyroid malignancies. Defining the associatio…

Resveratrol: distribución, propiedades y perspectivas

2013

Resveratrol is a natural polyphenol which can be found in many plants and fruits, such as peanuts, mulberries, blueberries and, above all, in grapes and red wine. Its synthesis is regulated by the presence of stressful factors, such as fungal contamination and ultra-violet radiation. In plants, it plays a role as a phytoalexin, showing a capacity to inhibit the development of certain infections. Plant extracts which contain resveratrol have been employed by traditional medicine for more than 2000 years. Resveratrol was first isolated, and its properties were initially studied with scientific methods, thirty years ago. Its in vitro properties have been extensively studied and demonstrated. I…

Sex Differences in Mitochondrial Antioxidant Gene Expression

2020

Females live longer than males. This could be in part due to the higher levels of estrogens in females, which protect them against aging. Physiological concentrations of estrogens have antioxidant effects as they induce the expression of manganese superoxide dismutase and glutathione peroxidase by stimulating estrogen receptors and the mitogen-activated protein kinase and nuclear factor kappa B pathways. However, estrogens can have undesirable effects such as they are feminizing to males, so other alternatives need to be searched. Phytoestrogens are good candidates as they can also bind to estrogens receptors, and in fact, they are able to mimic the antioxidant properties of estrogens. It i…