Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Hydroxyestrones”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 505 records · Page 28Linked to original sources
PubMed1998

Do urinary oestrogen metabolites predict breast cancer? Guernsey III cohort follow-up.

This is the first prospective study of urinary measures of the two major competing pathways of oestrogen metabolism, 16alpha-hydroxyoestrone (16alpha-OHE1) and 2-hydroxyoestrone (2-OHE1), in relation to incident breast cancer risk. Experimental and case-control study results suggest that metabolism favouring the more oestrogenic 16alpha-OHE1 pathway may be linked to higher breast cancer risk. Women aged 35 and older from Guernsey (n = 5104) were surveyed in 1977-85 and have been continuously monitored for breast cancer and mortality up to the present (Guernsey III, Imperial Cancer Research Fund). Incident cases of breast cancer were matched to three control subjects for comparison of urinary oestrogen metabolite levels measured by enzyme immunoassay (EIA) in spot urine samples collected at baseline and stored frozen for up to 19 years. Consistent with case-control study results, post-menopausal (but not premenopausal) women at baseline who went on to develop breast cancer showed about a 15% lower 2:16alpha-OHE1 ratio than matched control subjects. Further, subjects with metabolite ratios in the highest tertile of 2:16alpha-OHE1 had about a 30% lower risk than women with ratios in the lowest two-thirds, although results were not statistically significant (OR = 0.71, 95% CI = 0.29-1.75). It is of potential importance that, in contrast to most risk factors for breast cancer, such as late age at first birth, oestrogen metabolism appears to be modifiable via diet and exercise, offering women the possibility of lowering breast cancer risk through non-pharmacological measures, although this remains to be tested.

Adult↗
PubMed1999

Role of estradiol metabolism and CYP1A1 polymorphisms in breast cancer risk.

The endogenous metabolism of estrogens is primarily oxidative and involves hydroxylation of the steroid at either C2 (2-OHE1) or C16 (16-OHE1). While the 2-OHE1 metabolites are essentially devoid of peripheral biological activity, 16-OHE1 is an estrogen agonist. There is evidence of an association between the 2-OHE1/16-OHE1 metabolites ratio and breast cancer risk. The CYP1A1 gene may play a role in the 2-hydroxylation (2-OH) of estradiol. African-American women with the wild-type CYP1A1 gene showed a significant increase in the 2-OHE1/16-OHE1 ratio, from 1.35 +/- 0.56 at baseline to 2.39 +/- 0.98 (p = 0.006) after 5 days of treatment with indole-3-carbinol (400 mg/day), a 2-OHE1 inducer. Women with the Msp1 polymorphism showed no significant increase, (0.37% +/- 0.17%). In a case-control study involving 57 women with breast cancer and 312 female controls, the frequency of the homozygous Msp1 polymorphism was 4.2% in African-American controls and 16% in African-American breast cancer cases. The odds ratio of breast cancer with the Msp1 homozygous variant was 8.4 (95% confidence interval: 1.7-41.7). This association was not observed in Caucasian women. The other CYP1A1 polymorphisms were not associated with breast cancer. The CYP1A1 Msp1 polymorphism may be a marker of altered estradiol metabolism and of increased susceptibility to estrogen-related breast cancer in African-Americans.

Adult↗
PubMed1986

Increased 2-hydroxylation of estradiol as a possible mechanism for the anti-estrogenic effect of cigarette smoking.

Epidemiologic data indicate that cigarette smoking is associated with an important anti-estrogenic effect, and increased hepatic metabolism has been suggested as a possible mechanism. We examined the hypothesis that cigarette smoking in women induces an increase in estradiol 2-hydroxylation. This irreversible metabolic pathway yields 2-hydroxyestrogens, which possess minimal peripheral estrogenic activity and are cleared rapidly from the circulation. We found a significant increase in estradiol 2-hydroxylation in premenopausal women who smoked at least 15 cigarettes per day. The extent of the reaction (mean +/- SEM) was 53.6 +/- 2.2 percent among 14 smokers and 35.1 +/- 1.8 percent among 13 nonsmoking controls--an increase of approximately 50 percent (P less than 0.001). The extent of 2-hydroxylation among five smokers did not vary during the follicular and luteal phases of their menstrual cycles. In addition, urinary excretion of estriol relative to estrone was significantly decreased among smokers (P less than 0.01), providing evidence that the smoking-induced increase in 2-hydroxylation diminishes the competing metabolic pathway involving 16 alpha-hydroxylation. This study demonstrates that smoking exerts a powerful inducing effect on the 2-hydroxylation pathway of estradiol metabolism, which is likely to lead to decreased bioavailability at estrogen target tissues. Elucidation of the mechanism responsible for smoking-induced changes in 2-hydroxylation may be useful in the development of strategies to reduce the risk of hormone-dependent tumors.

Adult↗
PubMed1996

Effects of dietary broccoli on human in vivo drug metabolizing enzymes: evaluation of caffeine, oestrone and chlorzoxazone metabolism.

Ingestion of cruciferous vegetables may prevent chemically induced carcinogenesis by their influence on specific cytochrome P450 enzymes (CYP) and phase II drug metabolizing enzymes in humans and rodents. Thus CYP enzymes are involved in transformation of procarcinogens, mutagens, steroid hormones and a large variety of other endogenous and exogenous components. In order to learn more about the influence of cruciferous vegetables on drug metabolizing enzymes in man two CYP enzymes previously suggested to be induced by vegetables were selected in an in vivo experiment in humans. Sixteen healthy non-smoking subjects, two females and 14 males, were exposed to three different types of diets and afterwards assayed for CYP1A2 catalysed caffeine metabolites and for CYP2E1 catalysed 6-hydroxylation of chlorzoxazone. Further, 2-hydroxyoestrone:16 alpha-hydroxylation ratios were determined in urine by means of a monoclonal antibody-based enzyme immunoassay. The three dietary periods were: (A) a customary home diet; (B) a 6 day standard diet avoiding well-known dietary inducers and inhibitors of CYP; (C) a 12 day dietary supplement to the standard diet of 500 g/day broccoli. The average 6-hydroxychlorzoxazone:chlorzoxazone ratio decreased by 21% (P < 0.05) after diet B compared with diet A in a 2 h plasma sample after ingestion of 500 mg chlorzoxazone. The ratio increased by 19% after diet C, however, this was not statistically significant. The caffeine metabolic ratio (CMR) was determined in urine 6 h after ingestion of 100 mg caffeine. The mean CMR increased by 5.5% when changing from diet A to diet B. When shifting to diet C the mean CMR increased a further 19% (P < 0.0005). The average 2-hydroxyoestrone:16 alpha-hydroxyoestrone ratio decreased by 1.3% when comparing diet A with diet B. Daily broccoli intake increased the ratio by 29.5% (P < 0.05). A low correlation of CMR with the 2-hydroxyoestrone:16 alpha-hydroxyoestrone ratio indicates that human CYP1A2 and other CYP enzymes involved in oestrone 2-hydroxylation are induced by dietary broccoli. On the other hand, the catalytic activity of CYP2E1 is not affected to the same degree by dietary broccoli.

Adult↗
PubMed1983

Catechol-O-methyltransferase activity in erythrocytes of persons with severe thermal injury.

In the present investigation, we found that the catechol-O-methyltransferase activity (COMT) in erythrocytes of persons with severe thermal injury was strikingly increased when compared with that in erythrocytes of noninjured individuals. The specific activity of COMT in erythrocytes of burned patients was not correlated with extent of burn. Thus the echinocytes of burned persons are another example of abnormal red cells in which COMT activity is increased. This appears to be the first example of increased COMT activity in abnormal erythrocytes that is not associated with large numbers of reticulocytes.

Adult↗
PubMed2006

Regulation of catechol-O-methyltransferase expression in human myometrial cells.

OBJECTIVE: The catechol-O-methyltransferase enzyme catalyzes the methylation of the catechol estrogens, 2- or 4-hydroxyestrogen, to 2- or 4-methoxyestrogen. Both the hydroxy estrogens and methoxy estrogens were shown to modulate the effects of estrogen. Because catechol-O-methyltransferase activity controls levels of these metabolites, it may help regulate the cellular estrogenic milieu. In this study, we examined the regulation of catechol-O-methyltransferase expression in human myometrial cells. METHODS: Catechol-O-methyltransferase expression was assessed by reverse transcription-polymerase chain reaction, Western blot, and luciferase assays in human myometrial cells after treatment with estrogen or progesterone. Catechol-O-methyltransferase expression was measured in cells after treatment with tumor necrosis factor alpha (TNFalpha) alone or with lactacystin, a proteasome inhibitor. Luciferase assays were also conducted using human myometrial cells containing an estrogen response element-luciferase reporter gene to measure levels of estrogen-mediated transactivation after treatment with estrogen and increasing concentrations of 2-hydroxestrogen. RESULTS: Catechol-O-methyltransferase expression was down-regulated by progesterone or estrogen. Tumor necrosis factor alpha upregulated catechol-O-methyltransferase expression, whereas cotreatment with lactacystin attenuated this response, suggesting that TNFalpha activated nuclear factor kappa B to induce catechol-O-methyltransferase expression. Increased concentrations of 2-hydroxyestrogen attenuated estrogen-mediated transcription in the myometrial cells. CONCLUSION: Catechol-O-methyltransferase expression may be regulated in the myometrium to control the local action of estrogen. Low levels of catechol-O-methyltransferase in the myometrium would result in an accumulation of 2-hydroxyestrogen and may antagonize the local effect of estrogen. High levels of catechol-O-methyltransferase in the myometrium would result in lower levels of 2-hydroxyestrogen and may increase sensitivity to estrogen.

Acetylcysteine↗
PubMed2001

Oestrogen and progesterone increase the levels of apoptosis induced by the human papillomavirus type 16 E2 and E7 proteins.

Human papillomavirus (HPV) type 16 infects the genital tract and is generally acknowledged to be a causative agent of cervical cancer. HPV infection alone is not sufficient to induce cervical cancer and other factors such as steroid hormones are thought to play a role in the establishment and/or progression of this disease. The HPV-16 E2 protein is required for virus replication and modulates viral gene expression whereas the HPV-16 E7 protein is required for cell transformation. We and others have shown that both the E2 and E7 proteins can induce apoptotic cell death in HPV-transformed and non-HPV transformed cell lines. Here we show that the steroid hormones oestrogen and progesterone can both increase the levels of E2- and E7-induced apoptosis. The oestrogen metabolite 16 alpha-hydroxyoestrone also increases E2- and E7-induced cell death and the dietary component indole-3-carbinol, which reduces the formation of 16alpha-hydroxyoestrone from oestrogen, blocks the effects of oestrogen. Thus the metabolism of oestrogen to 16 alpha-hydroxyoestrone appears to be required for the effects of this hormone on E2- and E7-induced cell death. We also show that the oestrogen receptor antagonist 3-hydroxytamoxifen blocks the effects of oestrogen on E2- and E7-induced cell death, whereas the anti-progesterone RU486 blocks the effects of both progesterone and oestrogen. We discuss these results in terms of the origin and progression of cervical cancer.

Apoptosis↗
PubMed1989

11 beta-hydroxy-9 beta-estrone.

C18H22O3, Mr = 286.37, trigonal, P3(2), a = 10.091 (1), c = 12.271 (1) A, V = 1082.1 A3, Z = 3, Dx = 1.318 Mg m-3, lambda(Cu K alpha) = 1.5418 A, mu = 0.667 mm-1, T = 298 K, F(000) = 462, final R = 0.056 for 1468 observed reflections. The pattern of intermolecular interaction associated with 11 beta-hydroxy substitution differs from that observed in more potent estrogens.

Chemical Phenomena↗
PubMed1990

Structure of 3-hydroxy-1-methyl-1,3,5(10)-estratriene-11,17-dione.

C19H22O3, Mr = 298.39, orthorhombic, P2(1)2(1)2(1), a = 11.332 (6), b = 14.596 (7), c = 9.567 (4) A, V = 1582.6 (5) A3, Z = 4, D chi = 1.252 Mg m-3, lambda(Mo K alpha) = 0.71073 A, mu = 0.0778 mm-1, F(000) = 640, T = 273 K, R = 0.067 for 1762 unique observed reflections where F greater than 2 sigma (F). The structure was studied to observe the effect of 1-methyl and 11-keto substitution. The 3-hydroxyl is hydrogen bonded to O11 at 2.76 A. The B ring is in a 7 alpha, 8 beta half-chair conformation. The molecule twists about the C(9)--C(10) bond to relieve the steric interaction between the 1-methyl and 11-keto groups. The C1--C10--C9--C11 torsion angle is 55 vs 33.5 degrees, the average of 38 estradiol analogue structures.

Estrone↗