2-hydroxyestradiol and 2-hydroxyestrone

Endometriosis is an estrogen dependent gynecological disease associated with altered microbial phenotypes. The association among endogenous estrogen, estrogen metabolites, and microbial dynamics on disease pathogenesis has not been fully investigated. Here, we identified estrogen metabolites as well as microbial phenotypes in non-diseased patients (n = 9) and those with pathologically confirmed endometriosis (P-EOSIS, n = 20), on day of surgery (DOS) and ~1-3 weeks post-surgical intervention (PSI). Then, we examined the effects of surgical intervention with or without hormonal therapy (OCPs) on estrogen and microbial profiles of both study groups. For estrogen metabolism analysis, liquid chromatography/tandem mass spectrometry was used to quantify urinary estrogens. The microbiome data assessment was performed with Next generation sequencing to V4 region of 16S rRNA. Surgical intervention and hormonal therapy altered gastrointestinal (GI), urogenital (UG) microbiomes, urinary estrogen and estrogen metabolite levels in P-EOSIS. At DOS, 17β-estradiol was enhanced in P-EOSIS treated with OCPs. At PSI, 16-keto-17β-estradiol was increased in P-EOSIS not receiving OCPs while 2-hydroxyestradiol and 2-hydroxyestrone were decreased in P-EOSIS receiving OCPs. GI bacterial α-diversity was greater for controls and P-EOSIS that did not receive OCPs. P-EOSIS not utilizing OCPs exhibited a decrease in UG bacterial α-diversity and differences in dominant taxa, while P-EOSIS utilizing OCPs had an increase in UG bacterial α-diversity. P-EOSIS had a strong positive correlation between the GI/UG bacteria species and the concentrations of urinary estrogen and its metabolites. These results indicate an association between microbial dysbiosis and altered urinary estrogens in P-EOSIS, which may impact disease progression.

Topics: Adult; Chromatography, Liquid; Dysbiosis; Endometriosis; Estradiol; Estrogens; Female; Humans; Hydroxyestrones; Microbiota; RNA, Ribosomal, 16S; Tandem Mass Spectrometry

Although 17β-estradiol (E2) deficiency has been linked to the development of osteoarthritis (OA) in middle-aged women, there are few studies relating other estrogens and estrogen metabolites (EMs) to this condition. We developed a high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) method to measure the levels of six EMs (i.e., estrone, E2, estriol, 2-hydroxyestrone, 2-hydroxyestradiol, and 16a-hydroxyestrone) in healthy pre- and postmenopausal women and women with OA. This method had a precision ranging from 1.1 to 3.1% and a detection limit ranging from 10 to 15 pg. Compared to healthy women, serum-free E2 was lower in the luteal and postmenopausal phases in women with OA, and total serum E2 was lower in postmenopausal women with OA. Moreover, compared to healthy women, total serum 2-hydroxyestradiol was higher in postmenopausal women with OA and total serum 2-hydroxyestrone was lower in both the luteal and follicular phases in women with OA. In conclusion, our HPLC-ESI-MS/MS method allowed the measurement of multiple biochemical targets in a single assay, and, given its increased cost-effectiveness, simplicity, and speed relative to previous methods, this method is suitable for clinical studies.

Topics: Adult; Aged; Chromatography, High Pressure Liquid; Estradiol; Estriol; Estrogens; Estrone; Female; Follicular Phase; Humans; Hydroxyestrones; Limit of Detection; Luteal Phase; Middle Aged; Osteoarthritis; Postmenopause; Premenopause; Spectrometry, Mass, Electrospray Ionization; Statistics, Nonparametric

Catechol-O-methyltransferase (COMT) enzyme catalyzes the methylation of the 2- or 4-hydroxyestrogens to 2- or 4-methoxyestrogens. Both the hydroxyestrogens and methoxyestrogens have been shown to block or enhance the effects of estrogen respectively. Our objective was to investigate the potential role of COMT in parturition and cervical ripening using a rat model. Immunohistochemistry was conducted to detect and localize the COMT protein in rat uterine tissues during pregnancy. We measured the longitudinal changes in urinary 2-hydroxyestrogen before, during, and after pregnancy in rats. Animal studies were conducted to determine the effect of treatment with a selective COMT inhibitor on (1) mifepristone-induced preterm birth and (2) cervical resistance to stretch in pregnant rats. The intensity of staining for the COMT protein differed within the luminal epithelium, uterine gland epithelium, endometrium, and myometrium during pregnancy. Levels of staining for the COMT protein in rat myometrium were highest on day 1 and lowest on days 8 and 13, but high levels returned by days 16 and 19 of pregnancy. The levels of urinary 2-hydroxyestrogen gradually increased in the first 2 weeks of pregnancy, peaked from days 16 to 18 of pregnancy, and then gradually returned to pre-pregnancy levels after delivery. The percentage of pups retained in the uterus of pregnant rats treated with both mifepristone and COMT inhibitor (48 +/- 15%) was significantly higher (P < 0.05) when compared with the value of pregnant rats treated with mifepristone alone (12 +/- 4%). The resistance to stretch was significantly higher (P < 0.05) in cervical tissues from the pregnant rats treated with COMT inhibitor (0.28) when compared with cervical tissues taken from rats treated with vehicle control (0.18). Modulation of COMT activity may play a role in the regulation of myometrial contractility and cervical ripening during pregnancy.

Topics: Animals; Benzophenones; Biomarkers; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Cervical Ripening; Cervix Uteri; Estradiol; Estriol; Female; Hydroxyestrones; Immunohistochemistry; In Vitro Techniques; Mifepristone; Models, Animal; Obstetric Labor, Premature; Pregnancy; Rats; Rats, Sprague-Dawley

DNA damage caused by catechol estrogens has been shown to play an etiologic role in tumor formation. Catechol estrogens are reactive to DNA and form several DNA adducts via their quinone forms. To explore the mutagenic properties of 2-hydroxyestrogen-derived DNA adducts in mammalian cells, N(2)-(2-hydroxyestrogen-6-yl)-2'-deoxyguanosine and N(6)-(2-hydroxyestrogen-6-yl)-2'-deoxyadenosine adducts induced by quinones of 2-hydroxyestrone, 2-hydroxyestradiol, or 2-hydroxyestriol were incorporated site-specifically into the oligodeoxynucleotides ((5)(')TCCTCCTCXCCTCTC, where X is dG, dA, 2-OHE-N(2)-dG, or 2-OHE-N(6)-dA). The modified oligodeoxynucleotides were inserted into single-stranded phagemid vectors followed by transfection into simian kidney (COS-7) cells. Preferential incorporation of dCMP, the correct base, was observed opposite all 2-OHE-N(2)-dG adducts. Only targeted G --> T transversions were detected; the highest mutation frequency (18.2%) was observed opposite the 2-OHE(2)-N(2)-dG adduct, followed by 2-OHE(1)-N(2)-dG (4.4%) and 2-OHE(3)-N(2)-dG (1.3%). When 2-OHE-N(6)-dA adducts were used, preferential incorporation of dTMP, the correct base, was observed. Targeted mutations representing A --> T transversions were detected, accompanied by small numbers of A --> G transitions. The highest mutation frequencies were observed with 2-OHE(1)-N(6)-dA and 2-OHE(3)-N(6)-dA (14.5 and 14.1%, respectively), while 2-OHE(2)-N(6)-dA exhibited a mutation frequency of only 6.0%. No mutations were detected with vectors containing unmodified oligodeoxynucleotides. Thus, 2-OHE quinone-derived DNA adducts are mutagenic, generating primarily G --> T and A --> T mutations in mammalian cells. The mutational frequency varied depending on the nature of the 2-OHE moiety.

Topics: Animals; Base Sequence; Cell Line, Transformed; Chromatography, Liquid; COS Cells; DNA Adducts; DNA Mutational Analysis; Estradiol; Estrogens, Catechol; Estrone; Genetic Vectors; Hydroxyestrones; Kidney; Mass Spectrometry; Molecular Sequence Data; Mutagens; Oligodeoxyribonucleotides; Quinones; Transfection

Estrogen metabolism is altered in most, if not all, breast cancer tumors. These alterations primarily lead to the formation of the catechol estrogen metabolites, 2- and 4-hydroxyestrogens, which can generate superoxide anion radicals (O(2)(*)(-)) through the redox cycling of semiquinone/quinone derivatives. In breast cancer cells, the activity of nitric oxide synthase is also frequently elevated, resulting in an increased level of exposure to nitric oxide ((*)NO). Since (*)NO rapidly reacts with O(2)(*)(-) to produce the peroxynitrite anion (ONOO(-)), this study was undertaken to determine whether ONOO(-) can be generated when 2- and 4-hydroxyestrogens are incubated in vitro with (*)NO donor compounds. Using dihydrorhodamine 123 as a specific probe for ONOO(-) formation, a ratio of 100 microM dipropylenetriamine NONOate (DPTA/NO) to 10 microM 4-hydroxyestradiol (4-OHE(2)) gave an optimal ONOO(-) production of 11.9 +/- 1.9 microM (mean +/- SD). Quantification of ONOO(-) was not modified by mannitol, supporting the idea that the hydroxyl radical was not involved. This production of ONOO(-) required the presence of the catechol structure of estrogen metabolites since all methoxyestrogens that were tested were inactive. Hydroxyestrogen metabolites derived from estradiol showed the same efficiency in producing ONOO(-) as those originating from estrone. With DPTA/NO, the 4-hydroxyestrogens generated 30-40% more ONOO(-) than the 2-hydroxyestrogens. Optimal production of ONOO(-) was assessed with DPTA/NO and diethylenetriamine NONOate (initial (*)NO generation rates of 0.76 and 0.08 microM min(-1), respectively). With faster (*)NO-releasing compounds, such as diethylamine NONOate and spermine NONOate, lower levels of ONOO(-) were detected. These data suggest that once the optimal concentration of (*)NO was obtained, the reaction between (*)NO and 4-OHE(2) was saturated. The excess of (*)NO would probably react with aqueous oxygen to form nitrite (NO(2)(-)). Since the third-order reaction rate for the reaction between 2(*)NO and O(2) is 2 x 10(6) M(-2) s(-1), it can therefore be suggested that the reaction between (*)NO and 4-OHE(2) occurs at a faster rate.

Topics: Chromatography, High Pressure Liquid; Estradiol; Estrogens, Catechol; Hydroxyestrones; Mass Spectrometry; Nitrates; Nitric Oxide

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

Catechol estrogens are major estrogen metabolites in mammals and are the most potent naturally occurring inhibitors of catecholamine metabolism. These estrogen compounds have been implicated in carcinogenic activity and the 4/2-hydroxyestradiol concentration has been shown to be elevated in neoplastic human mammary tissue compared to normal human breast tissue. Three human liver UDP-glucuronosyltransferases, UGT2B7, UGT1A1, and UGT1A3, have been shown to catalyze the glucuronidation of catechol estrogens and lead to their enhanced elimination via urine or bile. The present study was designed to study the kinetic interaction of expressed human UGT2B7(Y) or (H), UGT1A1, and UGT1A3 toward 2- and 4-hydroxycatechol estrogens. cDNAs encoding UGT2B7(Y) or (H), UGT1A1, and UGT1A3 were expressed in HK293 cells, and cell homogenates or membrane preparations were used to determine their glucuronidation ability. UGT2B7(Y) reacted with higher efficiency toward 4-hydroxyestrogenic catechols, whereas UGT1A1 and UGT1A3 showed higher activities toward 2-hydroxyestrogens. UGT2B7(H) catalyzed estrogen catechol glucuronidation with efficiencies similar to UGT2B7(Y). Flunitrazepam (FNZ), a competitive inhibitor of morphine glucuronidation in hepatic microsomes, competitively inhibited catechol estrogen glucuronidation catalyzed by UGT2B7(Y), UGT1A1, and UGT1A3. Buprenorphine, an opioid substrate that reacts at high efficiency with each of these UGTs, was also studied. FNZ competitively inhibited buprenorphine glucuronidation with UGT1A1 and UGT2B7 but had no inhibitory activity toward UGT1A3. This suggests that buprenorphine and 2-hydroxycatechol estrogens react with separate active sites of UGT1A3. A catecholamine, norepinephrine, did not inhibit UGT2B7(Y)-, UGT1A1-, and UGT1A3-catalyzed glucuronidation of catechol estrogens. These results also suggest that drug-endobiotic interactions are possible in humans and may have implication in carcinogenesis.

Topics: Estradiol; Estrogens, Catechol; Flunitrazepam; Glucuronates; Glucuronosyltransferase; Humans; Hydroxyestrones; Isoenzymes; Norepinephrine

The comparative mitogenic activities of 17beta-estradiol (E2) and four metabolites, 2-hydroxyestradiol (2-OHE2), 2-hydroxyestrone (2-OHE1), 16alpha-hydroxyestradiol (16alpha-OHE2) and 16alpha-hydroxyestrone (16alpha-OHE1) were determined in estrogen receptor (ER)-positive MCF-7 and T47D human breast cancer cells. E2 (1 nM) induced a 7- to 13-fold increase in cell number in both cell lines compared to untreated cells and the mitogenic potencies of 16alpha-OHE1 or 16alpha-OHE2 were comparable to or greater than E2. In contrast, 2-OHE1 and 2-OHE2 were weak mitogens in both cell lines and in cells cotreated with 1 nM E2 and 100 or 1000 nM 2-OHE1 or 2-OHE2, there was a significant inhibition of hormone-induced cell proliferation. The comparative ER agonist/antagonist activities of E2 and the metabolites on transactivation were determined in T47D cells transiently transfected with constructs containing promoter inserts from the cathepsin D (pCD) and creatine kinase B (pCKB) genes. E2, 16alpha-OHE2 and 16alpha-OHE1 induced reporter gene activity in both MCF-7 or T47D cells transfected with pCKB or pCD. In contrast, 2-OHE1 and 2-OHE2 did not exhibit ER agonist activity for these transactivation assays, but in cells cotreated with E2 plus 2-OHE1 or 2-OHE2, there was a significant decrease in the hormone-induced response. These results demonstrate that 16alpha-OHE1/16alpha-OHE2 exhibit estrogenic activities similar to that observed for E2, whereas the 2-catecholestrogens are weak ER agonists (cell proliferation) or antagonists (cell proliferation and transactivation).

Topics: Breast Neoplasms; Cathepsin D; Cell Division; Creatine Kinase; Estradiol; Estriol; Female; Humans; Hydroxyestrones; Isoenzymes; Promoter Regions, Genetic; Receptors, Estrogen; Recombinant Proteins; Transfection; Tumor Cells, Cultured

The present work is determined to observe the effects of E2 (estradiol), 2-OHE1 (2-hydroxyestrone), 2-OHE2 (2-hydroxyestrodiol) on the proliferation of rat anterior pituitary cells (APC) in vitro by laser scanning confocal microscopy.. 10(-6) mol/L E2 stimulated the growth of APC. After 2 days of incubation with E2, the DNA content of APC increased to 1.3 times of the control group (P < 0.01). 10(-6) mol/L 2-OHE2 (other than 2-OHE1) stimulated proliferative activity of APC and inhibited the inhibitory effect of peribidil (10(-5) mol/L), a dopamine receptor agonist, on the poliferative activity of rat APC.

Topics: Animals; Cell Division; Cells, Cultured; Dopamine Antagonists; Estradiol; Hydroxyestrones; Male; Piribedil; Pituitary Gland, Anterior; Rats; Rats, Sprague-Dawley

Catecholestrogens (CE), 2-hydroxyestradiol, 2-hydroxyestrone and primary estrogens, estradiol and estrone were tested in their ability to compete for the high affinity uptake of [3H]-GABA into crude synaptosomal fractions. Aliquots of the crude synaptosomal fraction obtained from normal rats were incubated for 10 min at 37 degrees C with [3H]-GABA in the presence, or absence, of estrogens and catecholestrogens. Neither estradiol nor estrone modified the specific [3H]-GABA uptake into crude synaptosomal fractions. On the contrary, CE significantly affected the specific [3H]-GABA uptake in a dose-dependent manner: low concentrations of CE enhanced the uptake; this effect disappeared with high concentrations of the compounds. The stimulatory effect of CE on [3H]-GABA uptake was blocked when samples were coincubated with nipecotic acid, thus suggesting that this effect is specific rather than the result of non-specific interactions of CE with the hypothalamic membrane.

Topics: Animals; Estradiol; Estrogens, Catechol; Estrone; Female; gamma-Aminobutyric Acid; Hydroxyestrones; Hypothalamus; In Vitro Techniques; Nipecotic Acids; Proline; Rats; Rats, Sprague-Dawley; Synaptosomes; Tritium

In order to clarify the mechanism of antiatherogenic action of several steroids such as estrogens, dehydroepiandrosterone (DHEA) and dexamethasone, we investigated the effects of various steroids on the copper (Cu2+)-catalyzed oxidation of low density lipoprotein (LDL) or high density lipoprotein (HDL) in 0.15 M NaCl by measuring thiobarbituric acid-reactive substances (TBARS). At a concentration of 10(-5) M, estrogens strongly protected against LDL oxidation by 0.5 microM Cu2+ in the following order of inhibition: estradiol (E2) (75%), estrone (E1) (35%) and estriol (E3) (30%). However, the corresponding metabolites of these estrogens, the catechol estrogens, had an even more protective effect on LDL oxidation by 0.5 microM Cu2+ in the following order of inhibition: 2-hydroxyestradiol (2-OHE2) (98%), 2-OHE1 (97%) and 2-OHE3 (96%). E2 and 2-OHE2 from 10(-7) M to 10(-5) M inhibited LDL oxidation in a dose-dependent manner, with a more marked effect for oxidation by 0.1 microM Cu2+ than by 0.5 microM Cu2+. 10(-5) M dexamethasone produced a slight (10%) but significant inhibition of LDL oxidation by 0.5 microM Cu2+. In addition, the estrogens and catechol estrogens were also effective in protecting against HDL oxidation by 0.5 microM Cu2+. Other steroids including DHEA and DHEA-sulfate had no antioxidative effects on either LDL or HDL in this system. These results indicate that estrogens and their metabolites, the catechol estrogens, exert antioxidative effects on both LDL and HDL. The catechol estrogens may be more important antioxidants than estrogens for both LDL and HDL.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Antioxidants; Copper; Estradiol; Estriol; Estrogens; Estrogens, Catechol; Estrone; Humans; Hydroxyestrones; Lipid Peroxidation; Lipoproteins, HDL; Lipoproteins, LDL; Male; Oxidation-Reduction; Thiobarbituric Acid Reactive Substances

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

The effects of 2-hydroxy and 2-methoxy oestrogens on the extraneuronal O-methylation of 3H-(-)-noradrenaline were examined in progesterone-dominated, monoamine oxidase (MAO)-inhibited, rabbit uterine tissues in vitro. Both the corticosteroid-sensitive system in myometrium and the cocaine-sensitive system in endometrium were examined. In myometrial slices preincubated with nialamide to inhibit MAO and incubated with cocaine to inhibit neuronal uptake, 3H-normetanephrine (3H-NMN) formation was inhibited in the order of potency 2-hydroxy oestrone greater than or equal to 2-hydroxy oestradiol = 2-methoxy oestradiol greater than or equal to 2-methoxy oestrone. In myometrial slices not exposed to cocaine and nialamide, inhibition of 3H-NMN formation by both 2-hydroxy and 2-methoxy oestradiol did not affect the formation of deaminated metabolites of 3H-(-)-noradrenaline by the alternative metabolising pathway. In endometrial slices preincubated with nialamide to inhibit MAO, only 2-hydroxy oestrogens inhibited 3H-NMN formation, but they were one to two orders of magnitude less potent in this regard than in the myometrium. The uptake of 3H-(-)-noradrenaline by MAO- and COMT-inhibited myometrial slices was inhibited by 2-hydroxy and 2-methoxy oestrogens in the order of potency 2-methoxy oestradiol greater than or equal to 2-methoxy oestrone greater than or equal to 2-hydroxy oestrone greater than 2-hydroxy oestradiol. Uptake of 3H-(-)-noradrenaline by endometrial slices was not affected by either 2-hydroxy or 2-methoxy oestrogens.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 2-Methoxyestradiol; Animals; Catechol O-Methyltransferase Inhibitors; Endometrium; Estradiol; Estrogens, Catechol; Female; Hydroxyestrones; Methylation; Monoamine Oxidase Inhibitors; Myometrium; Norepinephrine; Rabbits; Tritium

Chronic administration of the catecholestrogens 2-OH-estrone (2-OH1) and 2-OH-estradiol (2-OHE2), of tamoxifen and its metabolites and of high concentrations of estradiol have been previously shown to inhibit the growth of the estrogen/progesterone receptor-positive transplantable prolactin (PRL)-secreting rat pituitary tumor 7315a. The mechanism of action of these inhibitory effects on tumor growth is unknown. In the present study we investigated the direct effects of these compounds on PRL release by a tumor cell clone derived from the 7315a tumor. E2 stimulated PRL release in FCSABS (10% estrogen-stripped fetal calf serum)-cultured tumor cells in a biphasic manner: at low concentrations (0.1-100 nM) there was a dose-dependent stimulation of PRL release, which decreased in response to 1 microM E2 and which was greatly inhibited by 10 microM E2. Both 2-OHE2 (100 nM and 1 microM) and 2-OHE2 (1 microM) inhibited PRL release by FCS-cultured tumor cells. In FCSABS-cultured tumor cells, 0.1-10 nM 2-OHE1 and 1 microM 2-OHE2 inhibited PRL release, but 1-100 nM 2-OHE2 stimulated PRL release. Tamoxifen (TMX) and its metabolites dihydroxy (di-OH-TMX) and 4-hydroxytamoxifen (4-OH-TMX) inhibited PRL in a dose-dependent manner. The PRL release inhibiting effect of 4-OH-TMX was 100 times more potent that those of TMX and di-OH-TMX, which were similar in their effect. The inhibitory effects of micromolar concentrations of the catecholestrogens on PRL release could be overcome by estradiol, while the inhibitory effects of high concentrations of tamoxifen were not prevented by estradiol. Both "endogenous" (catecholestrogens) and "exogenous" (tamoxifen and its metabolites) antiestrogens and very high concentrations of estradiol directly inhibit PRL secretion by cultured pituitary tumor cells. The mechanism of their anti-tumor effects, however, seems to differ. The catecholestrogens have direct anti-estrogenic effects on cultured tumor cells, which can be antagonized by estradiol. The final effect of their mixed antagonistic/agonistic action depends on the presence or absence of estrogens in the culture medium. Tamoxifen also affects tumor growth probably mainly via a direct effect, partly involving anti-estrogenic and partly direct toxic effects.

Topics: Animals; Dose-Response Relationship, Drug; Estradiol; Estrogen Antagonists; Estrogens, Catechol; Female; Hydroxyestrones; Pituitary Neoplasms; Prolactin; Rats; Rats, Inbred BUF; Secretory Rate; Tamoxifen; Tumor Cells, Cultured

The administration of 100 micrograms 2-hydroxyestrone (2-OHE1) or 2-hydroxyestradiol-17 beta (2-OHE2) at 0900h or 1000h in the morning of proestrus into normal 4-day cycling rats results in suppression of the preovulatory LH surge in the afternoon of that day. The LH-RH content of the median eminence in control rats decreases sharply in the afternoon from elevated noon levels. However, the catechol estrogen-treated rats do not show this decrease. These results indicate that the catecholestrogens block the preovulatory LH surge by preventing the release of LH-RH from the median eminence, but do not interfere with the synthesis and accumulation of LH-RH. Furthermore, injections of non-uterotropic 2-OHE1 twice at 30 minutes intervals into ovariectomized rats fail to affect the LH tonic secretion by 180 minutes after the initial injection. These data indicate that catechol estrogen interferes with the brief neuronal triggering phase necessary for LH-RH release, but does not affect the LH tonic secretion which is an estrogen-independent process.

Topics: Animals; Estradiol; Estrogens, Catechol; Female; Follicular Phase; Gonadotropin-Releasing Hormone; Hydroxyestrones; Luteinizing Hormone; Median Eminence; Rats; Rats, Inbred Strains

Estrone (E1), estradiol (E2), the catechol estrogens 2-OHE1 and 2-OHE2, and diethylstilbestrol (DES) were incubated with purified prostaglandin synthase (PHS) in vitro in the presence of arachidonic acid and their PHS-catalyzed cooxidation was determined. 2-OHE1, 2-OHE2, and DES were extensively metabolized by PHS peroxidase activity, E1 and E2 to a lesser extent. The cooxidation of the estrogens is accompanied by an increased prostaglandin formation and an increase in cyclooxygenase activity in vitro; progesterone and nylestriol are without effect. Prostaglandins have been proposed to play a role in events related to early estrogen action in tissues such as the uterus. The cooxidation of estrogens and their metabolites by prostaglandin hydroperoxidase might represent one type of interaction between the hormones and the arachidonic acid cascade that could lead to changes in prostaglandins.

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Diethylstilbestrol; Estradiol; Estrogens; Estrone; Hydroxyestrones; Male; Oxidation-Reduction; Prostaglandin-Endoperoxide Synthases; Prostaglandins; Seminal Vesicles; Sheep

Catechol estrogens, 2-hydroxy estrone, 2-hydroxy estradiol and 2-hydroxy estriol, were tested as possible antioxidants of phospholipid peroxidation induced by Fe3+-ADP-adriamycin, using phospholipid liposomes as lipid source and alpha-tocopherol or other steroids as reference compounds. The parameters of antioxidant activities were: elongation of induction period, inhibition of O2 consumption required for lipid peroxidation and inhibition of peroxidative cleavage of unsaturated phospholipid. Of the tested compounds, 2-hydroxy estradiol or 2-hydroxy estrone had more potent activity than that of tocopherol.

Topics: Adenosine Diphosphate; Animals; Antioxidants; Doxorubicin; Estradiol; Estriol; Estrone; Ferric Compounds; Hydroxyestrones; Kinetics; Lipid Peroxides; Liposomes; Microsomes, Liver; Oxygen Consumption; Phospholipids; Rats; Vitamin E

Cycling rats injected with 2-hydroxyestrone or 2-hydroxyestradiol at 09.00 or 10.00 h in the morning of proestrus do not express the normal preovulatory LH surge in the afternoon of the day. The LHRH content of the median eminence in control animals decreases sharply in the afternoon from elevated noon and morning levels. The catechol estrogen-treated rats fail to show the decrease. Thus the catechol estrogens block the LH surge at its usual time by influencing the changes in the concentration of LHRH in the median eminence on proestrus. Since the catechol estrogens have short biological half-lives, their effect on the LHRH content in the afternoon must originate in the morning at the time of the endogenous estradiol (E2) peak. These results have implications in the physiological processes responsible for the positive feedback of estradiol on the preovulatory LH surge in the rat.

Topics: Animals; Estradiol; Estrogens, Catechol; Estrus; Female; Gonadotropin-Releasing Hormone; Hydroxyestrones; Luteinizing Hormone; Median Eminence; Proestrus; Rats; Rats, Inbred Strains; Time Factors

Administration of 100 micrograms 2-hydroxyestrone (2-OHE1) on the morning of proestrus to 4 day cycling rats resulted in suppression of the preovulatory LH surge. The greatest response was observed when the injection of 2-OHE1 coincided with plasma estradiol levels that were close to but not at their maximal proestrus levels. Injection of 100 micrograms 2-hydroxyestradiol-17 beta (2-OHE2-17 beta) effectively inhibited the LH surge when given at 0800 or 0900h, but not when injected at 1000 or 1200h. Non estrogenic 2-hydroxyestradiol-17 alpha was effective in suppressing the LH surge when given at 0900 or 1000h. Neither 2-OHE1 nor 2-OHE2-17 beta interfered with LH secretion in response to LH-RH administration, indicating that the inhibitory action of the catecholestrogen is exercised at the hypothalamic level. However, 2-OHE1 given five times following the implantation of an estradiol capsule in ovariectomized rats had no effect on the LH surge elicited on the second day. These data indicate that catecholestrogen interferes with the brief neuronal triggering phase necessary for LH-RH release, but not the sensitization phase of positive feedback of estrogen on phasic LH secretion. The evidence also indicates that the action does not involve conventional competition for the estradiol receptor.

Topics: Animals; Estradiol; Estrone; Female; Follicular Phase; Gonadotropin-Releasing Hormone; Hydroxyestrones; Luteinizing Hormone; Ovariectomy; Proestrus; Rats; Rats, Inbred Strains

The 2-hydroxycatecholestrogens, 2-hydroxyestradiol [1,3,5-(10)estratriene-2,3,17 beta-triol] (2-OHE2) and 2-hydroxyestrone [2,3-dihydroxy-1,3,5-(10)-estratriene-17-one] (2-OHE1) were tested for their ability to alter PRL production and PRL messenger RNA (mRNA) levels in rat pituitary cell cultures. Treatment of cells with 10(-8) M 2-OHE1 or 2-OHE2 resulted in increased PRL secretion at 24 and 48 h (to 167% and 211% of control, respectively), but not at 4 h. Metabolism studies of radioactive 2-OHE1 and 2-OHE2 in parallel cultures demonstrated that the major metabolite at all times for either compound was the 2-methoxy derivative. After 24 h of treatment, nearly 40% of each compound was the original catecholestrogen, and at no time was there any detectable conversion to estradiol or estrone. Treatment of pituitary cells for 48 h with increasing concentrations of 2-OHE1 or 2-OHE2 resulted in a biphasic PRL dose response. PRL secretion was increased 3.6-fold for 2-OHE2 and 2.4-fold for 2-OHE1 between 10(-10) M and 10(-8) M. At concentrations above 5 X 10(-8) M, however, both compounds decreased PRL levels until, at 10(-6) M 2-OHE1 or 2-OHE2, PRL levels were 40-70% of control. Changes in PRL mRNA levels paralleled those of secretion. Treatment of pituitary cells with 10(-8) M of either 17 beta-estradiol (E2), 2-OHE1, or 2-OHE2 resulted in 2- to 5-fold increases in translatable and hybridizable PRL mRNA. The addition of 10(-7) M E2 plus 10(-8) M 2-OHE1 or 2-OHE2 resulted in PRL secretion and PRL mRNA levels equal to those resulting from E2 stimulation alone. The inhibition in PRL secretion and PRL mRNA levels caused by 10(-6) M 2-OHE1 or 2-OHE2 was partially overcome by coincubation of cultures with E2. Thus, 2-OHE1 and 2-OHE2 at low concentrations (less than 10(-8) M) can act on the pituitary as E2 agonists to increase PRL synthesis but at high concentrations may act as inhibitors of PRL production.

Topics: Animals; Cells, Cultured; Dose-Response Relationship, Drug; Estradiol; Estrone; Female; Hydroxyestrones; Nucleic Acid Hybridization; Pituitary Gland, Anterior; Prolactin; Rats; RNA, Messenger; Time Factors

The effects of catechol oestradiol and catechol oestrone on the release of LH and prolactin were investigated in immature male and female Wistar rats. In male rats both catechol oestradiol and catechol oestrone significantly increased the plasma concentration of LH, and catechol oestradiol but not catechol oestrone significantly increased the plasma concentration of prolactin and decreased the pituitary concentration of LH. The parent oestrogens, oestradiol-17 beta and oestrone, had no effect on plasma LH concentrations, but both increased significantly the plasma concentration of prolactin, and oestrone but not oestradiol-17 beta increased the pituitary concentration of LH. In immature female rats, catechol oestradiol inhibited the surge of LH and the increase in uterine weight induced by injecting pregnant mare serum gonadotrophin (PMSG). The injection of oestrone induced an increase in the plasma concentration of LH which was about nine times greater than that produced by oestradiol-17 beta. There were no significant differences in the effects of these steroids on plasma prolactin concentration. These results (i) confirm that in the immature male rat catechol oestrogens can stimulate LH release and show that catechol oestradiol can increase prolactin release, (ii) show that catechol oestradiol can inhibit the stimulatory effects of PMSG on LH release and uterine weight in the immature female rat, and (iii) demonstrate that oestrone can stimulate LH release in the immature female rat.

Topics: Animals; Estradiol; Estrogens, Catechol; Female; Gonadotropins, Equine; Hydroxyestrones; Luteinizing Hormone; Male; Organ Size; Ovary; Pituitary Gland; Prolactin; Rats; Rats, Inbred Strains; Sexual Maturation; Uterus

Since catechol estrogens are potent competitive inhibitors of catechol-O-methyl transferase (COMT), it has been suggested that they may prolong the half-life of catecholamines which in turn can cause hypertension. Thus, experiments were carried out to study the effect of catechol estrogens on blood pressure in the male rat following chronic administration. Results demonstrate that 2-hydroxyesterone (2,3-dihydroxyestra-1,3,5(10)-trien-17-one) and 2-hydroxy-estradiol (estra-1,3,5(10)-triene-2,3,17 beta-triol) even when administered in high doses do not alter blood pressure.

Topics: Animals; Blood Pressure; Catechol O-Methyltransferase Inhibitors; Drug Implants; Estradiol; Estrogens, Catechol; Hydroxyestrones; Male; Rats

In a series of experiments it has been shown that 4-hydroxyestradiol (4-OHE2) as well as 2-hydroxyestradiol (2-OHE2) are involved in regulatory mechanisms of LH secretion in the miniature pig. Two-hydroxyestrone (2-OHE1) and 1-hydroxyestradiol-benzoate (1-OHE2B), however, have no significant effects on LH secretion. Moreover the studies indicate a regional specificity in the action of 4-OHE2, 2-OHE2 and estradiol (E2). 4-OHE2 and 2-OHE2 decrease plasma LH when given into the ventromedial nucleus of the hypothalamus and increase plasma LH levels when microinjected into the dorsomedial nucleus of the hypothalamus. Whereas E2 affects LH secretion when it is given into the area dorsalis of the hypothalamus and fornix. In addition the experiments performed on female and male rats to measure the effects of 2-OHE2 and 2-OHE1 on turnover rates of dopamine, norepinephrine and epinephrine in the anterior mediobasal hypothalamus and medial preoptic area show that the effects of catecholestrogens may partly be mediated by catecholamines.

Topics: Animals; Brain; Castration; Dopamine; Epinephrine; Estradiol; Estrogens, Catechol; Hydroxyestrones; Hypothalamus; Luteinizing Hormone; Male; Norepinephrine; Preoptic Area; Swine; Swine, Miniature

The catechol estrogens, the 2- or 4-hydroxylated metabolites of estrone and estradiol, have pharmacologic properties of both estrogens and catecholamines and are formed from estrogens in peripheral tissues and in the brain. This has led to speculation that they may mediate some of the feedback effects of estrogens upon gonadotropins and prolactin (PRL). Studies testing these hypotheses are still few and have not been conclusive. There have been reports that the catechol estrogen 2-hydroxyestrone (2-OHE1) might act as a partial estrogen antagonist, stimulating gonadotropin secretion; and that it might have dopamine-like effects, suppressing the secretion of PRL. In studies testing the chronic and acute effects of catechol estrogens on LH, FSH, and PRL in men and women, we found that they behaved as estrogens, suppressing gonadotropins when given in doses high enough to compensate for their rapid clearance and degradation. We found no evidence that they suppress PRL secretion. The weight of available evidence suggests that these effects are mediated by estrogen receptor interactions; and that the formation of catechol estrogens is not an obligatory step in the feedback effects of estrogens, although it may have a modulatory role. Plasma levels of catechol estrogens are too low for them to exert circulating neuroendocrine effects.

Topics: Animals; Dose-Response Relationship, Drug; Estradiol; Estrogens, Catechol; Estrone; Female; Follicle Stimulating Hormone; Follicular Phase; Humans; Hydroxyestrones; Kinetics; Luteinizing Hormone; Male; Prolactin; Rats; Reference Values

Plasma levels of 2-hydroxyestrone (2-OHE1) and 2-hydroxyestradiol (2-OHE2) were determined by a new radioimmunoassay which employed a short Sephadex LH-20 column chromatography for the purification of samples and the antiserum to 2-hydroxyestrone-17-(O-carboxymethyl)oxime-BSA conjugate for assay. The plasma value was below the detection limit for the assay (approximately 15 pg/ml) in men and non-pregnant women, but rose 20-200 pg/ml during pregnancy in 2-OHE1 and around 15 pg/ml in the 3rd trimester of pregnancy in 2-OHE2. There was no significant difference of plasma 2-OHE1 level between normal pregnancy and toxemic pregnancy with hypertension, in the 3rd trimester. The plasma level was very low in all of three subjects with the placental dysfunction in toxemic pregnancy. The plasma metabolic clearance rate (MRCp) of 2-OHE1 and 2-OHE2 were determined in normal adults by two methods; infusion of unlabeled 2-OHE1 and 2-OHE2 to equilibrium with radioimmunoassay of their plasma levels, and infusion of [3H]-2-OHE1 and [3H]-2-OHE2 to equilibrium with measurement of chromatographically purified their tritium. The MCRs by the former and latter methods was 40-70 X 10(3) and 15-50 X 10(3) in 2-OHE1, and 18-29 X 10(3) and 12-14 X 10(3) l/day in 2-OHE2, respectively. The major plasma metabolite comigrated with 2-methoxy compounds to each catecholestrogen. The t1/2 of disappearance rate by the method of infusion of unlabeled compounds was approx. 45 s in 2-OHE1 and 90 s in 2-OHE2. When [3H]-2-OHE1 and [3H]-2-OHE2 were incubated with blood samples of adults, 2-methoxy compounds also rapidly formed. From these results it is concluded that the extremely high MCRp of 2-OHE1 and 2-OHE2 make it unlikely these compounds circulate peripherally except in pregnancy in levels sufficient to produce the physiological effects on estrogen receptors or catecholamines.

Topics: Adult; Blood Pressure; Child; Child, Preschool; Estradiol; Estrogens; Estrogens, Catechol; Estrone; Female; Humans; Hydroxyestrones; Kinetics; Male; Menstruation; Metabolic Clearance Rate; Pre-Eclampsia; Pregnancy; Radioimmunoassay

To study the interactions of catecholestrogens with the catecholamine system we estimated the catecholamine concentrations and turnover rates in the anterior part of the mediobasal hypothalamus (AMBH) and medial preoptic area (MPO) following 2-hydroxyestradiol-17 beta (2-OHE2) or 2-hydroxyestrone (2-HOE1) treatment in castrated male and female rats. Serum concentrations of LH and prolactin were also measured. The turnover rates of catecholamines were calculated by monitoring the catecholamine loss 1 h after blocking the catecholamine synthesis with alpha-methyl-p-tyrosine. Dopamine, epinephrine and norepinephrine concentrations were measured by a radioenzymatic assay. In males, 2-OHE2 (50 micrograms/kg) and 2-OHE1 (50 micrograms/kg) resulted in decreased serum LH values (p less than 0.05) 4 and 5 h after treatment. None of these 2-hydroxylated estrogens were able to alter serum prolactin levels significantly. There was a decline in epinephrine and norepinephrine concentrations in the AMBH. The greatest change in catecholamine turnover rates in response to catecholestrogen treatment also occurred in the AMBH. 2-OHE2 and 2-OHE1 reduced turnover rates of dopamine, norepinephrine and epinephrine in the AMBH. Only the dopamine turnover rate was affected in the MPO, where it increased following 2-OHE2 treatment. In females, only 2-OHE2 (50 micrograms/kg) was effective in decreasing serum LH (p less than 0.05) and increasing prolactin (p less than 0.01) levels. Dopamine and epinephrine concentrations as well as their turnover rates declined in the AMBH after treatment with catecholestrogens. The concentration and turnover rate of epinephrine also decreased in the MPO. There was no significant change in norepinephrine concentration or turnover rate. It is suggested that 2-hydroxyestrogens are possibly involved in mechanisms which are inhibitory to LH secretion and stimulatory to prolactin release. These actions appear to be partly mediated by catecholamines.

Topics: Animals; Castration; Dopamine; Epinephrine; Estradiol; Estrone; Female; Hydroxyestrones; Hypothalamus; Male; Norepinephrine; Preoptic Area; Rats; Rats, Inbred Strains; Sex Factors

We investigated the effects of peripheral administration of 17 beta-estradiol (E2), estrone (E1), and the catecholestrogens, 2-hydroxyestradiol (2-OHE2) and 2-hydroxyestrone (2-OHE1), on anterior pituitary gland LH release in the prepuberal rat. Steroids in oil were injected sc into 25-day-old female and 35- to 40-day-old male rats. The injection of E2, E1, or 2-OHE2 caused a surge in serum LH levels in female rats 48 h later, during the after hours. Only E1 induced a LH surge 24 h after injection. The positive effects of 2-OHE2 in the females were only observed if a massive dose was administered, the steroid was injected on 2 consecutive days, or E2 or progesterone was given to 2-OHE2-primed rats. The 2-OHE1 was totally ineffective in causing a serum LH surge under a variety of experimental protocols. In male rats, the injection of any one of the four steroids decreased serum LH levels. Even the injection of E2 or 2-OHE2 for 2 days or the injection of E2 in 2-OHE2-primed rats failed to elevate the serum LH concentration in male rats. The results suggest that 2-OHE2 and E1 could play a role in the preovulatory release of LH in the female; 2-OHE2 and 2-OHE1 could play a role in the negative feedback control of LH release in the male.

Topics: Animals; Estradiol; Estrogens, Catechol; Estrone; Feedback; Female; Hydroxyestrones; Luteinizing Hormone; Male; Rats; Rats, Inbred Strains; Sexual Maturation

We investigated the effects of the peripheral administration of 17 beta-estradiol (E2), estrone (E1), and the catecholestrogens, 2-hydroxyestradiol (2-OHE2) and 2-hydroxyestrone, (2-OHE1), on anterior pituitary gland PRL release in the prepuberal rat. Steroids in oil were injected sc into 25-day-old female and 35- to 40-day-old male rats. The injection of E2, E1, or 2-OHE2, but not of 2-OHE, caused a surge in serum PRL levels in female rats 48 h later, during the afternoon hours. Only E1 induced a PRL surge 24 h after injection. In male rats, the injection of E1 or 2-OHE2, but not of 2-OHE1, elevated serum PRL levels on a chronic basis. The results suggest that 2-OHE1 plays no discernible role in PRL release in either sex, but that 2-OHE2 might play a role in the tonic release of PRL in the male and in the preovulatory release of PRL in the female.

Topics: Animals; Estradiol; Estrogens, Catechol; Estrone; Female; Hydroxyestrones; Male; Prolactin; Rats; Rats, Inbred Strains; Receptors, Dopamine; Sexual Maturation

A high performance liquid chromatographic method is described for the rapid, non-destructive separation of a number of physiologically important steroidal estrogens, including the labile catechol estrogens. This procedures uses a "Diol" column and gradient elution to separate in a single run, estrogens ranging from 2-methoxy estrone, one of the least polar C18 steroids, to estriol, one of the most polar. Simpler, isocratic conditions, are provided for the separation of estrogens of similar polarity. A semi-preparative column of similar composition was used for the purification of samples containing 25 to 50 mg of individual steroids.

Topics: Chromatography, High Pressure Liquid; Estradiol; Estrogens; Estrogens, Catechol; Hydroxyestrones

Recently it has been attached importance to the physiological function of catecholestrogens. To elucidate it a specific radioimmunoassay of conjugated 2-hydroxyestrone (2-OHE1) and 2-hydroxyestradiol-17 beta (2-OHE2) in human plasma was attempted. After extracting with ethyl acetate, samples were purified by a short Sephadex LH-20 columnchromatography and determined using the antiserum to 2-OHE1-17(O-carboxymethyl) oxime-bovine serum albumin conjugate. The following results were obtained: 1) A long Sephadex LH-20 columnchromatography which was used for the purification of catecholestrogens produced chemically, had a superior faculty in separation and high capacity 2) The antiserum cross-reacted 26.4% with 1-OHE2, but less than 1% with other steroid hormones. 3) The sensitivity of the method was around 10pg in both 2-OHE1 and 2-OHE2 assays. The method blank determined using 2ml plasma of bilaterally adreno-oophrectomized women was below 15 pg/ml in both 2-OHE1 and 2-OHE2 assays (n = 24). 4) The coefficient of variation in both accuracy and between-assay precision of the method was less than 17%. 5) The plasma 2-OHE1 concentration was below 15 pg/ml in normal men (n = 8) and non-pregnant women (n = 13). The concentration in pregnant women was 20 +/- 8 pg/ml (SD, n = 7) in 1st trimester of pregnancy, 58 +/- 13 (n = 3) in 2nd trimester and 177 +/- 66 (n = 12) in 3rd trimester. The E1/2-OHE1 and E2/2-OHE1 ratios in 3rd trimester of 9 pregnant women were 19.7 +/- 11.9(SD) and 78.0 +/- 27.8, respectively. 6) The plasma 2-OHE2 concentration was below 15 pg/ml in normal men (n = 8), non-pregnant women (n = 8), and 1st to 2nd trimester (n = 10) and 15 +/- 9 pg/ml (SD, n = 13) in 3rd trimester of pregnant women.

Topics: Adult; Cross Reactions; Estradiol; Estrogens, Catechol; Estrone; Female; Humans; Hydroxyestrones; Male; Pregnancy; Radioimmunoassay

The effects of primary and catechol oestrogens on the uterus of the immature rat were compared. Because differences between the in-vivo and in-vitro oestrogenic actions of catechol oestrogens on the secretion of LH had been observed, their effects on a peripheral target organ, the uterus, were examined under similar conditions. In-vivo effects were assessed by measurement of uterine weight, induction of uterine cytoplasmic progestogen receptors, and by histological examination. In-vitro actions were determined by measurement of oestrogen-specific induced protein. It was found that the uterotrophic effects in vivo of 4-hydroxyoestradiol were indistinguishable from those of oestradiol whereas 2-hydroxyoestradiol was only weakly oestrogenic and 2-hydroxyoestrone had no effect. However, in vitro, 2-hydroxyoestradiol was as effective as 4-hydroxyoestradiol or oestradiol in stimulating synthesis of uterine induced protein, and 2-hydroxyoestrone, although less potent than oestradiol, had a significant effect. These results were consistent with the observed effects on the secretion of LH. The differences between in-vivo and in-vitro uterotrophic properties of catechol oestrogens can be explained on the basis of known pharmacokinetic factors.

Topics: Animals; Estradiol; Estrogens; Estrogens, Catechol; Estrone; Female; Hydroxyestrones; Organ Size; Rats; Rats, Inbred Strains; Sexual Maturation; Uterus

Topics: Animals; Estradiol; Estrogens, Catechol; Female; Hydroxyestrones; Methylation; Propiophenones; Protein Biosynthesis; Rats; Rats, Inbred Strains; Receptors, Estrogen; Subcellular Fractions; Tissue Distribution; Uterus

Plasma levels of 2-hydroxyestradiol (2-OHE2) were measured using a new RIA procedure. Values were below the detection limit of the assay (less than 10 pg/ml), except in the third trimester of pregnancy, when they rose to approximately 15 pg/ml. The infusion of 130 microgram/h purified 2-OHE2 elevated its plasma concentration to 155 pg/ml, consistent with a plasma MCR (MCRp) of approximately 20,000 liters/day. The infusion of [3H] 2-OHE2 to equilibrium and chromatographic separation of the extracted plasma metabolites yielded an MCRp of about 13,000 liters/day; the major plasma metabolite comigrated with 2-methoxyestradiol, and [3H] xi-methoxyestrone was also formed. The MCRp, of 2-OHE2 is approximately half that of 2-hydroxyestrone (2-OHE1), but much higher than those of other steroids. As is true for 2-OHE1, the clearance of 2-OHE2 must occur primarily in the blood compartment. Together, the measured MCRp values and estrogen receptor affinities of 2-OHE2 and 2-OHE1 predict a relative potency for effects upon gonadotropin secretion which is close to that observed in vivo.

Topics: 2-Methoxyestradiol; Adult; Chromatography, Ion Exchange; Chromatography, Paper; Chromatography, Thin Layer; Estradiol; Female; Half-Life; Humans; Hydroxyestrones; Male; Metabolic Clearance Rate; Middle Aged; Radioimmunoassay

Topics: Adrenal Glands; Animals; Estradiol; Estriol; Estrone; Female; Hydroxyestrones; Neoplasm Transplantation; Organ Size; Ovary; Pituitary Gland; Pituitary Neoplasms; Prolactin; Rats; Uterus

Topics: Animals; Blood Flow Velocity; Castration; Dose-Response Relationship, Drug; Estradiol; Estrone; Female; Hydroxyestrones; Pregnancy; Sheep; Uterus; Vasodilation

We have examined the ability of various steroids to compete for high-affinity binding of 3H-labeled ligands to catecholamine receptors in membranes prepared from rat cerebral cortex, striatum, and anterior pituitary. Ligands employed were: [3H]WB4101, [3H]prazosin, [3H]yohimbine, and [3H]clonidine (alpha-noradrenergic); [3H]dihydroalprenolol (beta-noradrenergic); [3H]spiperone and [3H]ADTN (dopaminergic). Only the 17 beta estrogens were effective and only binding of [3H]spiperone and [3H]ADTN in striatum and [3H]WB4101 and [3H]prazosin in cerebral cortex was reduced. Thus putative dopaminergic and alpha 1-noradrenergic sites alone appear to recognize estrogens. A slight competitive effect on [3H]spiperone binding to anterior pituitary membranes was also observed. Among the 17 beta estrogens tested, the most effective in all cases was the catechol estrogen 2-hydroxyestradiol (2-OHE2). The ability of 2-OHE2 (IC50 = 20-30 micro M) to inhibit ligand binding to alpha 1 receptors was comparable to that of norepinephrine (IC50 = 10-20 micro M), whereas for dopamine receptors in striatum and pituitary 2-OHE2 was an order of magnitude less effective than dopamine (IC50 = 12 micro M) in reducing binding of 3H ligands. Estradiol-17 beta and 2-hydroxyestrone were also able to inhibit binding, but the order of steroid potency was different for alpha 1 and dopaminergic receptors. Progesterone, testosterone, and corticosterone were without effect in all cases. These results show that there is specificity of steroid interactions with catecholamine receptors in the brain, both in terms of steroid structure and receptor type. The possible relevance of these interactions to neuroendocrine function is discussed.

Topics: Animals; Binding, Competitive; Brain; Cerebral Cortex; Corpus Striatum; Dioxanes; Estradiol; Estrogens; Female; Hydroxyestrones; Pituitary Gland, Anterior; Prazosin; Rats; Receptors, Adrenergic; Spiperone; Tetrahydronaphthalenes

Temporal alterations in plasma prolactin levels caused by the administration of 2-hydroxyestradiol and 2-hydroxyestrone (100 microgram/kg) into the right atrium of freely-moving conscious male rats were examined. The catechol estrogens were given in a single bolus via an indwelling cannula and plasma prolactin concentration was monitored by taking blood samples every 2 min. A pulsatile elevation of plasma prolactin occurred approximately 4 h after the injection of 2-hydroxyestradiol and a small increase was also observed when it was administered to rats bearing a Silastic capsule containing estradiol. 2-Hydroxyestrone had no effect in untreated male rats but produced a 5- to 6-fold elevation in plasma prolactin level 4 h after its administration to rats implanted with estradiol. It is proposed that 2-hydroxyestrone suppresses the action of estradiol on prolactin secretion from the pituitary and that the accumulated hormone is released when the concentration of this catechol estrogen falls below a critical level. A longer latent period was required to produce an elevation in plasma prolactin levels by 2-hydroxyestradiol than by estradiol.

Topics: Animals; Drug Implants; Drug Interactions; Estradiol; Estrogens, Catechol; Hydroxyestrones; Kinetics; Male; Prolactin; Rats; Rats, Inbred Strains

We have examined the effect of the catechol oestrogens 2-hydroxyoestradiol (2-OHE2), 4-hydroxyoestradiol (4-OHE2) and 2-hydroxyoestrone (2-OHE1) and their corresponding primary oestrogens on secretion of LH and FSH by enzymatically dispersed rat anterior pituitary cells in monolayer culture. Basal LH levels in the medium were significantly higher than in control wells when cells were exposed to 10(-8) M-oestradiol-17 beta for 40 h: oestrone and all three catechol oestrogens (in the same doses) also stimulated basal LH concentrations to levels quantitatively similar to those seem after oestradiol treatment. The same effects were observed when steroids were given at 10(-9) mol/l. Oestradiol, 2-OHE2, and 4-OHE2 but not 2-OHE1 increased pituitary responsiveness to LH releasing hormone (LH-RH) (given in a range of doses from 10(-11) to 10(-6) mol/l). The responses of cells treated with 2-OHE2 and 4-OHE2 were similar, though less than the response seen after treatment with oestradiol. This contrasts with the very different oestrogenic effects of 2- and 4-OHE2 previously observed in vivo. Neither oestradiol nor the catechol oestrogens had any effect on basal or LH-RH-stimulated FSH release.

Topics: Animals; Cells, Cultured; Estradiol; Estrogens, Catechol; Estrone; Female; Follicle Stimulating Hormone; Hydroxyestrones; Luteinizing Hormone; Pituitary Gland, Anterior; Rats; Secretory Rate; Stimulation, Chemical

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Estradiol; Estrogens, Catechol; Estrone; Female; Humans; Hydroxyestrones; Prostaglandins; Prostaglandins E; Prostaglandins F; Rats; Uterus

Topics: Animals; Behavior, Animal; Brain; Cell Nucleus; Cytosol; Estradiol; Estrogens, Catechol; Estrone; Female; Glucosephosphate Dehydrogenase; Hydroxyestrones; Pituitary Gland; Posture; Rats; Receptors, Estrogen; Receptors, Progesterone

Topics: Animals; Catechols; Enzyme Induction; Estradiol; Estriol; Estrogens; Estrogens, Catechol; Female; Hydroxyestrones; Peroxidases; Rats; Structure-Activity Relationship; Uterus

The response of serum prolactin to the catechol estrogens, 2-hydroxyestrone (2-OH E1) and 2-hydroxyestradiol (2-OH E2) and their primary estrogens, estrone (E1) and estradiol (E2), was studied in 35-day-old male rats. The subcutaneous administration of 50 microgram of 2-OH E1 or 2-OH E2 significantly suppressed serum prolactin concentrations, but they were not significantly altered by the administration of 50 microgram of E1 or E2.

Topics: Animals; Catechol O-Methyltransferase; Catechols; Estradiol; Estrogens; Estrogens, Catechol; Hydroxyestrones; Luteinizing Hormone; Male; Prolactin; Rats

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Cell Nucleus; Cytosol; Estradiol; Estriol; Estrogens; Female; Hydroxyestrones; Mammary Neoplasms, Experimental; Rats; Receptors, Estrogen; Uterus

Topics: Animals; Castration; Dose-Response Relationship, Drug; Estradiol; Estrone; Female; Follicle Stimulating Hormone; Hydroxyestrones; In Vitro Techniques; Luteinizing Hormone; Pituitary Gland; Receptors, Estrogen; Sheep

When [6,7-3H]estradiol was incubated with tissue homogenates of the brain, the pituitary, and the liver of two human female fetuses, a number of radioactive metabolites more "polar" than the incubated substrate were detected. Among these, the identification of two types of catecholestrogens, i.e. the 2- and 4-hydroxyestrogens, was of major interest. Compared on the basis of wet weight of tissues (250 mg), the conversion of estradiol to 2-hydroxyestrogens (2-hydroxyestradiol and 2-hydroxyestrone) was 0.8% in the frontal cortex, 1.0% in the hypothalamus, 2.1% in the pituitary, and 7.8% in the liver. For the first time, the formation of 4-hydroxyestrogens was demonstrated. The percentages of incubated estradiol hydroxylated at C-atom 4 (4-hydroxyestradiol and 4-hydroxyestrone) were 0.5 in the cortex, 0.4% in the hypothalamus, .1% in the pituitary, and 0.5% in the liver. The results show that fetal brain and pituitary tissue can hydroxylate estradiol in positions 2 and 4 to a similar extent, whereas in the liver, about 15 times more 2-hydroxy than 4-hydroxy compounds are formed. Moreover, the 2-hydroxylating capacity of the liver is definitely greater than that of the brain, whereas the 4-hydroxylating capacity is about the same as that of the brain.

Topics: Brain; Estradiol; Estrogens, Catechol; Female; Humans; Hydroxyestrones; Hydroxylation; Liver; Pituitary Gland