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  • enzymes
  • The steroid is known to compete with catecholamines for binding to catechol O-methyltransferase and tyrosine hydroxylase and to directly and competitively inhibit these enzymes. (wikipedia.org)
  • Polymorphisms in maternal or offspring genes encoding estrogen-metabolizing enzymes may influence prenatal catechol estrogen levels and could therefore be biomarkers of TGCC risk. (aacrjournals.org)
  • Variation in maternal or offspring genes encoding estrogen-metabolizing enzymes could influence the level of exposure to prenatal catechol estrogens and could therefore serve as biomarkers in a retrospective study of hormonal risk factors for TGCC. (aacrjournals.org)
  • However, for such studies to be valid, it is important to correctly identify the enzymes involved in estrogen bioactivation. (aacrjournals.org)
  • UDP-glucuronosyltransferases are a family of membrane-bound enzymes involved in the inactivation and elimination of catechol estrogens through glucuronidation. (aacrjournals.org)
  • hormone
  • The authors suggested that 2-hydroxylated estrogens may mediate the action of the hormone parent, having properties distinct but relevant to the physiology or pathophysiology of a target organ. (aacrjournals.org)
  • The estrogen:ER complex binds to specific DNA sequences called a hormone response element to activate the transcription of target genes (in a study using an estrogen-dependent breast cancer cell line as model, 89 such genes were identified). (wikipedia.org)
  • Androgens
  • Quantitatively, estrogens circulate at lower levels than androgens in both men and women. (wikipedia.org)
  • Estrone, as well as the other estrogens, are synthesized from cholesterol and secreted mainly from the gonads, though they can also be formed from adrenal androgens in adipose tissue. (wikipedia.org)
  • bind
  • This relationship led us to postulate that oxidation of catechol estrogens (CE) to CE quinones (CE-Q) results in electrophilic intermediates that also covalently bind to DNA and form depurinating adducts. (pnas.org)
  • reactive
  • 2-Hydroxyestradiol, as well as 2-hydroxyestrone and 4-hydroxyestradiol, can undergo metabolic redox cycling to generate free radicals like superoxide and reactive estrogen semiquinone/quinone intermediates. (wikipedia.org)
  • genes
  • implicated 4-OH-E2 in the induction of estrogen-responsive genes, a response that exhibited partial or no abrogation by coadministration with an antiestrogen, providing evidence for the ability of 4-OH-E2 to carry out genetic upregulation via a pathway independent of ER signalling. (wikipedia.org)
  • tumors
  • The association with UDT, which has been associated with high gestational estrogen levels ( 2 , 3 ), and the early age at onset of these tumors strongly suggest that tumor-initiating events occur during gestation, possibly by rendering germ cells susceptible to malignant transformation. (aacrjournals.org)
  • The implication of estrogens in development of tumors at various organ sites of both animals and humans has been universally recognized over the last 70 years. (aacrjournals.org)
  • Estrogens induce tumors in laboratory animals and have been associated with breast and uterine cancers in humans. (semanticscholar.org)
  • Inactivation
  • Catechol O-methyl transferase catalyzes O-methylation of mutagenic flavonoids: Metabolic inactivation as a possible reason for their lack of carcinogenicity in vivo J. Biol. (springer.com)
  • pregnancy
  • Exposure to relatively high circulating maternal estrogen levels during pregnancy has long been suspected as being a risk factor for TGCC. (aacrjournals.org)
  • Although data from animal models have strongly and consistently supported this hypothesis, epidemiologic studies have collectively produced equivocal results, possibly due to a reliance on self-reported surrogates of estrogen levels, such as pregnancy characteristics ( 1 ). (aacrjournals.org)
  • Another type of estrogen called estetrol (E4) is produced only during pregnancy. (wikipedia.org)
  • citation needed] In baboons, blocking of estrogen production leads to pregnancy loss, suggesting estradiol has a role in the maintenance of pregnancy. (wikipedia.org)