In addition to the direct effect of estrogen on mitochondria and the redox cycling of catechol estrogen
, estrogen-induced proinflammatory cytokines, such as IL-1[beta], IL-6, and TNF-[alpha], can also generate reactive oxygen and nitrogen species (RO/NS) .
quinones as initiators of breast and other human cancers: implications for biomarkers of susceptibility and cancer prevention.
* Cytochrome P450 1B1 (CYP1B1) catalyses the conversion of estrone and estradiol to potentially carcinogenic catechol estrogen
CYP1A1 and CYP1B1 catalyze hydroxylation of the A-ring of estradiol ([E.sub.2]) to form the catechol estrogen
2- or 4-hydroxyl estradiol (2-OH-[E.sub.2] or 4-OH-[E.sub.2], respectively).
(free form) has been considered as one of the most likely candidates, acting as an endogenous antioxidant (6).
Differential spatiotemporal regulation of lactoferrin and progesterone receptor genes in the mouse by primary estrogen, catechol estrogen
, and xenoestrogen.
metabolites and conjugates in mammary tumors and hyperplastic tissue from estrogen receptor-alpha knock-out (ERKO)/Wnt-1 mice: implications for initiation of mammary tumors.
* Estrogens stimulate the (ortho)sympathetic nervous system directly and through conversion into catechol estrogens
, making women excited and enthusiastic, but excess estrogens render women nervous, aggressive, and anxious.
Simpson, "Potentiation of epinephrine-induced lipolysis by catechol estrogens
and their methoxy derivatives," Endocrinology, vol.
Additionally, direct cancerogenic effects of estrogens can occurs via formation of electrophilic, redox-active estrogen ortho-quinones from catechol estrogens
. The concurrent formation of reactive oxygen species and superoxide anions can damage DNA and cellular proteins .
Anti oxidant activities of estrogens against aqueous and lipophillie radicals; differences between phenol and Catechol estrogens
. Chem Phys Lipids 2000; 105: 179-88.
The catechol estrogens
. Journal of Steroid Biochemistry, 15: 111-124.