ascorbic-acid and 2-hydroxyestrone

Catechol estrogens are considered critical intermediates in estrogen-induced carcinogenesis. We demonstrated previously that 17beta-estradiol (E(2)), estrone (E(1)) and four of their catechol estrogens, 2- and 4-hydroxyestradiols (2- and 4-OHE(2)), and 2- and 4-hydroxyestrones (2- and 4-OHE(1)) induce morphological transformation in Syrian hamster embryo (SHE) fibroblasts, and the transforming abilities vary as follows: 4-OHE(1) > 2-OHE(1) > 4-OHE(2) > 2-OHE(2) vertical line E(2), E(1). To examine the involvement of catechol estrogens in the initiation of hormonal carcinogenesis, we studied the ability of E(2), E(1) and their catechol estrogens to induce DNA adducts in SHE cells by using a (32)P-post-labeling assay. DNA adducts were detected in cells treated with each of all the catechol estrogens at concentrations of 10 microg/ml for 1 h and more. 2- or 4-OHE(2) formed a single DNA adduct, which was chromatographically distinct from each other. In contrast, 2- or 4-OHE(1) produced one major and one minor adduct, and the two adducts formed by each catechol estrogen exhibited identical mobilities on the chromatograms. Neither E(2) nor E(1) at concentrations up to 30 microg/ml induced DNA adducts. The abilities of the estrogens to induce DNA adducts were ranked as follows: 4-OHE(1) > 2-OHE(1) > 4-OHE(2) > 2-OHE(2) > > E(2), E(1), which corresponds well to the transforming and carcinogenic abilities of the estrogens. In addition, the level of DNA adducts induced by the catechol estrogens was markedly decreased by co-treatment of cells with the antioxidant L-ascorbic acid. The results indicate the possible involvement of oxidative metabolites of catechol estrogens of E(2) and E(1) in the initiation of endogenous estrogen-induced carcinogenesis.

Topics: Animals; Antioxidants; Ascorbic Acid; Cell Survival; Cell Transformation, Neoplastic; Cricetinae; DNA Adducts; Estradiol; Estrogens, Catechol; Fibroblasts; Hydroxyestrones; Mesocricetus

Compounds like indole-3-carbinol (I3C) have been shown to increase catechol estrogen formation and reduce mammary tumor incidence in mice. These compounds may exert a protective effect for breast cancer development by decreasing the overall estrogen pool available for the formation of 16 alpha-hydroxyestrone (16 alpha-OHE1), a metabolite that retains significant estrogenic activity, may be mutagenic and could represent a potential carcinogenic intermediate of estradiol degradation. I3C and ascorbigen originate from the breakdown of glucobrassicin. We have compared the inductive effects of I3C with ascorbigen and beta-naphthaflavone (Bnf) in microsomes from rats pretreated with these compounds using isotope dilution GC-MS and a radiometric method. Incubated microsomes from rats pretreated with I3C and ascorbigen yielded high levels of 2-hydroxyestradiol (2-OHE2) that were comparable to levels induced by Bnf and were significantly above control group levels (p < 0.005). Absolute values determined by the radiometric method were approximately 40% lower than 2-OHE2 concentrations determined by GC-MS, although the relative changes in each group were the same. These differences may be attributed to the radiolabel becoming trapped in microsomal intermediates in the sequence leading to tritium entering the aqueous compartment. Both ascorbigen- and Bnf-treated animals exhibited significant increases in 2-hydroxyestrone (2-OHE1) (p < 0.05). The ability of ascorbigen to induce estradiol C-2 hydroxylation has not been previously reported. Based on these data, we speculate that ascorbigen will act as an anticarcinogenic agent and will inhibit or reduce the incidence of mammary tumor formation.

Topics: Animals; Ascorbic Acid; Benzoflavones; beta-Naphthoflavone; Estradiol; Estrogens, Catechol; Female; Gas Chromatography-Mass Spectrometry; Hydroxyestrones; Hydroxylation; Indoles; Microsomes, Liver; Radiometry; Rats; Rats, Sprague-Dawley

Plasma levels of 2-hydroxyestrone (2-OHE1) were measured by specific radioimmunoassay during puberty to elucidate the physiological role of this hormone on female sexual development. Plasma levels of FSH, LH, PRL and estradiol (E2) were also measured with an RI-kit. 67 girls between aged 6 and 16 were selected for this study. Blood samples were collected into tubes containing 0.1W/V% EDTA and 0.1W/V% ascorbic acid and immediately centrifuged. 2-OHE1 in plasma was extracted and separated with a Sephadex LH-20 column. RIA was applied using anti 2-OHE1-17-CMO-BSA. Plasma 2-OHE1 levels before menarche were low (6-7 pg/ml) until 10 years of age. The levels started to increase from 11 and reached 11.2 +/- 5.8pg/ml at 16 years of age. The levels of 2-OHE1 in girls after menarche were significantly higher than that before menarche (p less than 0.01). There was a significant correlation between 2-OHE1 and E2 in girls before menarche (p less than 0.001, r = 0.5416). However, the 2-OHE1 to E2 ratio decreased significantly from 9 to 10 years of age. These results indicate that during this period, the E2 increase is more predominant than that of 2-OHE1. There was a significant negative correlation between 2-OHE1 and PRL after menarche while no correlation between 2-OHE1 and FSH, LH was noticed. These results suggested that 2-OHE1 may play a role in sexual development after menarche rather than in the initiation of menarche.

Topics: Adolescent; Age Factors; Ascorbic Acid; Child; Estradiol; Estrone; Female; Follicle Stimulating Hormone; Gonadal Steroid Hormones; Humans; Hydroxyestrones; Luteinizing Hormone; Prolactin; Puberty; Radioimmunoassay