Cardiovasc Res. 2002 Feb 15;53(3):627-33.
Isoproterenol amplifies 17 beta-estradiol-mediated vasorelaxation: role of endothelium/nitric oxide and cyclic AMP.

Chan HY, Yao X, Tsang SY, Bourreau JP, Chan FL, Huang Y.

Department of Physiology, Chinese University of Hong Kong, Shatin, Hong Kong, China.

OBJECTIVES: Estrogen exerts cardiac protection via multiple cellular mechanisms. Estrogen modifies vasodilatation induced by certain relaxants such as beta-adrenoceptor agonists. However, little is known whether low concentrations of beta-adrenoceptor agonists would reciprocally influence the acute relaxant response to estrogen. The present study was designed to investigate the synergistic interaction between isoproterenol and 17 beta-estradiol, and the role of endothelium and cyclic AMP-dependent pathway in this interaction. METHODS: Changes in vessel tone of the isolated rat mesenteric artery rings were measured using a force-displacement Grass transducer. RESULTS: In 9,11-dideoxy-11 alpha, 9 alpha-epoxy-methanoprostaglandin F(2 alpha)-preconstricted endothelium-intact rings, 17 beta-estradiol induced relaxations with pD(2) of 5.06 +/- 0.06. Pretreatment of endothelium-intact rings with isoproterenol (1-3 x 10(-9) M, 1 h incubation time) significantly enhanced 17 beta-estradiol-induced relaxation. This effect was inhibited by Rp-cGMPS triethylamine (3 x 10(-6) M), and abolished in the presence of 3 x 10(-5) M N(G)-nitro-L-arginine methyl ester or in endothelium-denuded rings. The effect of isoproterenol was antagonized by propranolol (3 x 10(-6) M), ICI 118,551 (3 x 10(-6) M), but not by atenolol (10(-5) M). Rp-cAMPS triethylamine (3 x 10(-6) M) abolished the effect of isoproterenol. Besides, exposure to 3 x 10(-9) M forskolin for 1 h also potentiated the relaxant response to 17 beta-estradiol. CONCLUSION: In endothelium-intact rat mesenteric arteries pretreatment with low concentrations of isoproterenol enhanced the acute relaxant response to 17 beta-estradiol. This enhancement was dependent on




J Cardiovasc Pharmacol. 2002 Mar;39(3):347-53.
17-beta estradiol preserves endothelial cell viability in an in vitro model of homocysteine-induced oxidative stress.

Dimitrova KR, DeGroot KW, Suyderhoud JP, Pirovic EA, Munro TJ, Wieneke J, Myers AK, Kim YD.

Department of Anesthesia, Georgetown University School of Medicine, Washington, DC 20007, USA.

High levels of homocysteine (Hcy) accelerate endothelial cell damage by producing hydrogen peroxide (H(2)O(2)). We investigated whether 17-beta estradiol may prevent the accelerated rate of endothelial cell detachment and reduced cell viability in cultured endothelial cells challenged with Hcy. Cultured bovine aortic endothelial cells (BAEC) were incubated for 72-h with either vehicle (alcohol) or different concentrations of 17-beta estradiol (1 nM [1E2] and 10 nM [10E2]) before being challenged with 0.5 mM of Hcy. Cell viability and H(2)O(2) levels were evaluated at 30 min, 1-, 2-, 4-, 8-, and 24-h after adding Hcy. Cell suspensions were frozen in liquid nitrogen and used later for spectrophotometric measurement of intracellular glutathione (GSH) levels. Cell viability 24 h after Hcy administration was significantly lower in vehicle versus 1 nM and 10 nM 17-beta estradiol (44 +/- 5% vs. 70.66 +/- 4%, [p < 0.001] and 79 +/- 5% respectively, [p < 0.001]). H(2)O(2) levels were higher in vehicle (1 +/- 0.05 microM) compared with 1E2 and 10E2 (0.8 +/- 0.1 microM, p = 0.02 and 0.1 +/- 0.05 microM, respectively, p < 0.001), whereas GSH content was increased in 1E1 and 10E2 versus control (27.69 +/- 4.6 nM/10(6) cells and 43.49 +/- 5.5 nM/10(6) cells vs. 13.33 +/- 1.5 nM/10(6) cells, p < 0.001). Bovine aortic endothelial cells treatment with 17-beta estradiol (0, 1, and 10 nM) and 0.1 mmol buthionine sulfoximine, an inhibitor of gamma-glutamylcysteine synthase, abolished the beneficial effects of estradiol alone on cell viability, GSH content, and H2O2 generation. Estradiol prevents Hcy-induced endothelial cell injury by increasing the intracellul




Am J Ther. 1996 Aug;3(8):574-579.
Serum Estradiol and Estrone Levels During 3 Weeks of Alternate-Site and Same-Site Applications of a Once-A-Week Drug-in-Adhesive Transdermal Estradiol Patch.

Harrison LI, Riedel DJ, Reynolds SJ, Kolars CA, Chang SF, Edgren AR, Nelson JR.

3M Pharmaceuticals, Departments of Pharmacokinetics and Drug Metabolism, Clinical Research, Statistical Data Services and Analytical Research and Development, St. Paul, MN, USA.

This open-label, randomized crossover trial was conducted in healthy postmenopausal women to characterize the serum estradiol and estrone profiles from a once-a-week transdermal estradiol patch applied repeatedly to the same site or to alternate sites on the abdomen over a 3-week period. Similar mean serum estradiol and estrone profiles and circulating estradiol:estrone ratios of approximately 1.0 were observed for both patch application regimes. Repeated application to the same or alternate sites did not result in an accumulation of exogenous estradiol or in a statistically significant increase in application-site reactions. Although the once-a-week transdermal estradiol patch should be applied to alternate sites to reduce the likelihood of dermatologic reactions, accidental application site overlap should not result in an increase in serum estradiol and estrone concentrations.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11862293&dopt=Abstract estradiol [PubMed - as supplied by publisher]




Psychopharmacology (Berl). 2002 Jan;159(3):275-83. Epub 2001 Oct 12.
Effects of gonadal steroid hormone treatments on opioid antinociception in ovariectomized rhesus monkeys.

Negus SS, Mello NK.

Alcohol and Drug Abuse Research Center, Harvard Medical School, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA. neguclean.harvard.edu

RATIONALE: Gonadal steroid hormones altered opioid antinociception under some conditions in rodents, and we reported previously that chronic estradiol enhanced kappa but not mu opioid antinociception in ovariectomized rhesus monkeys. Sex differences have also been observed in the antinociceptive effects of opioid agonists. These findings suggest that gonadal hormones may modulate opioid antinociception. OBJECTIVES: To extend our previous studies of estradiol by examining the effects of progesterone alone, estradiol in combination with progesterone, and testosterone alone on opioid antinociception in ovariectomized rhesus monkeys. METHODS: Opioid effects were studied during chronic treatment with vehicle (sesame oil) or with progesterone alone (P; 0.32 mg/kg per day), a combination of progesterone+estradiol (P+E; 0.32 mg/kg per day P + 0.002 mg/kg per day E), or testosterone alone (T; 0.32 mg/kg per day). Opioid antinociception in a warm-water tail-withdrawal procedure was examined with the selective kappa opioid agonist U50,488, the selective mu agonist morphine, and the two mixed-action opioids butorphanol and nalbuphine. RESULTS: The steroid treatment regimens produced physiological levels of progesterone and estradiol similar to peak levels observed during the luteal phase of the menstrual cycle and physiological levels of testosterone similar to those observed in intact males. Treatment with P, P+E, or T did not alter baseline thermal nociception. P+E significantly increased the potency of U50,488 at 50 degrees C but not at 54 degrees C. Gonadal hormone treatments had little or no effect on antinociception produced by morphine, butorphanol, or nalbuphine at either temperature. CO




J Dairy Sci. 2002 Jan;85(1):43-50.
A GnRH/LH surge without subsequent progesterone exposure can induce development of follicular cysts.

Gumen A, Sartori R, Costa FM, Wiltbank MC.

Department of Dairy Science, University of Wisconsin-Madison 53706, USA.

Our hypothesis was that follicular cysts would develop if cows experienced an estradiol-induced GnRH LH surge in the absence of an ovulatory follicle. Further, we hypothesized that estradiol would fail to induce a subsequent GnRH/LH surge in these cows until they were treated with progesterone. In experiment 1, seven cows were synchronized with a controlled internal drug releasing device (CIDR) for 9 d and each received 500 microg of cloprostenol on d 7. All follicles (> or = 5 mm in diameter) were aspirated at the time of CIDR removal using transvaginal follicular aspiration. Two days after aspiration, cows were treated with 5 mg of estradiol benzoate (EB) to induce a GnRH/LH surge in the absence of an ovulatory-sized follicle. All cows had an LH surge following the estradiol treatment and three of seven developed an anovulatory condition that resembled follicular cysts. The four cows that did not develop follicular cysts luteinized remaining cells from one aspirated follicle each. Thus, all cows with a progesterone elevation after the estradiol/GnRH/LH surge had subsequent ovulatory cycles, whereas the absence of progesterone was followed by follicular cysts. After 49 d, the anovulatory cows were induced back to normal cyclicity by insertion of a CIDR for 7 d. In two subsequent experiments, nine of 26 cows were induced to have follicular cysts by follicular aspiration followed by 5 mg of EB. After 26 d of observation, all cystic cows received a second treatment with 5 mg of EB and none of the cows showed an LH surge or ovulation. Cystic cows were untreated (n = 4 controls) or treated for 7 d with a CIDR (n = 5). All cystic cows were subsequently treated for a third time with 5 mg of EB. All CIDR-treated cows had an LH surge and ovula




Toxicol Lett. 2002 Mar 10;128(1-3):129-44.
Estradiol, testosterone, dehydroepiandrosterone and androstenedione: novel derivatives and enantiomers. Interactions with rat liver microsomal cytochrome P450 and antioxidant/radical scavenger activities in vitro.

Klinger W, Lupp A, Karge E, Baumbach H, Eichhorn F, Feix A, Fuldner F, Gernhardt S, Knels L, Kost B, Mertens G, Werner F, Oettel M, Romer W, Schwarz S, Elger W, Schneider B.

Institute of Pharmacology and Toxicology, Friedrich Schiller University Jena, Nonnenplan 4, D-07743 Jena, Germany.

Interactions of 27 steroids, among them 17 derivatives such as ethers, sulfates and amidosulfonates derived from 17 beta- and 17 alpha-estradiol, from testosterone and alpha- and beta-dihydrotesosterone and from dehydroepiandrosterone with rat liver microsomal cytochromes P450 (P450) were investigated in vitro by assessing binding to P450 and effects on P450 mediated monooxygenase functions as measured by different model reactions: ethoxyresorufin O-deethylation (EROD), ethoxycoumarin O-deethylation (ECOD) and ethylmorphine N-demethylation (EMND). With the exception of 17 alpha-estradiol-3-dimethylamidosulfonate, estrone, its -3-methylether and -3-amidosulfonate and testosterone, all other steroids displayed type I or reverse type I binding to P450. All steroids inhibited EROD activity in micromolar concentrations. An additional strong inhibition of ECOD and EMND activities was only demonstrated for the androgens and progestins. Estriol, estrone and mestranol displayed less inhibitory actions on the model reactions than estradiol. No major differences in comparison to the parent compounds were noted with the other derivatives. The only exceptions were 17 beta-(8,9-dehydro-14 alpha,15 alpha-methylene)estradiol, which displayed stronger effects than estradiol, and dehydroepiandrosterone-3-sulfate, which was less effective than dehydroepiandrosterone. Possible antioxidant properties of the steroids were examined by the stimulated lipid peroxidation (LPO), H2O2




Biol Reprod. 2002 Mar;66(3):701-6.
Thyroid hormones mediate steroid-independent seasonal changes in luteinizing hormone pulsatility in the ewe.

Anderson GM, Connors JM, Hardy SL, Valent M, Goodman RL.

Department of Physiology, West Virginia University, Morgantown, West Virginia 26506, USA.

Thyroid hormones permit the increase in response to estradiol negative feedback in ewes at the transition to anestrus. In this study, we tested whether the thyroid hormones are also required for steroid-independent seasonal changes in pulsatile LH secretion. In experiment 1, Suffolk ewes were ovariectomized and thyroidectomized (THX) or ovariectomized only (controls) in late November. LH pulse frequency and amplitude were measured for 4 h in December, April, May, June, and August. Pulse frequency was also measured in the presence of estradiol-containing implants during the breeding (December) and early anestrus (March) seasons. As expected, in the presence of estradiol, pulse frequency declined between December and March in control but not THX ewes. In the absence of estradiol, a seasonal decline in frequency and an increase in amplitude occurred in control ewes, concurrent with lengthening photoperiod. A similar trend was seen in THX ewes, but the seasonal changes were lower in magnitude and not significant. In experiment 2, the same protocol was used (pulse measurements in December, May, and June) with a larger THX group size (n = 7). Results were similar to those of experiment 1 for controls. In THX ewes, pulse frequency did not change over time and was significantly elevated relative to that of controls during the summer. Pulse amplitude in THX ewes tended to increase during summer and did not differ from pulse amplitudes in control ewes. These results demonstrate that thyroid hormones are required for steroid-independent cycles in LH pulse frequency; however, some seasonal changes in amplitude still occur in the absence of thyroid hormones. This finding contrasts with the changes in estradiol ne




Hum Reprod. 2002 Mar;17(3):589-94.
Acute and chronic effects of genistein, tyrphostin and lavendustin A on steroid synthesis in luteinized human granulosa cells.

Whitehead SA, Cross JE, Burden C, Lacey M.

Department of Physiology, St George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, UK. s.whiteheaghms.ac.uk

BACKGROUND: Phytoestrogens, including genistein and other inhibitors of tyrosine kinases (TKs), inhibit specific steroidogenic enzymes. This study was designed to compare the effects of genistein, with two other TK inhibitors, on steroid synthesis in human granulosa luteal (GL) cells and to identify which steroidogenic enzymes they may affect. METHODS: GL cells, obtained from women undergoing IVF procedures, were cultured for various periods of time with and without substrates for progesterone and estradiol synthesis, in the presence or absence of the TK inhibitors. RESULTS: The TK inhibitors significantly suppressed progesterone and estradiol synthesis in a dose-dependent manner over a 48 h culture period. Progesterone production in the presence of 10(-7) mol/l pregnenolone during a 4 h period was inhibited by both acute (4 h) and chronic (24 h) exposure of GL cells to 50 micromol/l genistein (P < 0.05) whilst no significant effects of 50 micromol/l tyrphostin A23 were observed. Genistein (4 and 24 h exposure) inhibited the production of estradiol using 10(-7) mol/l estrone as a substrate, but inhibition of estradiol synthesis using androstenedione or testosterone as substrates was only observed after a 24 h exposure. In contrast, tyrphostin acutely stimulated estradiol synthesis when androstenedione and testosterone were used as substrates (P < 0.05) but not estrone. CONCLUSIONS: Genistein directly inhibits 3 and 17beta-hydroxysteroid dehydrogenase activity, whilst tyrphostin has an acute stimulatory effect on aromatase activity. Over a longer time (24 and/or 48 h period), both TK inhibitors suppress steroid synthesis.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11870108&dopt=Abstract estradiol [PubMed - ind




J Mol Recognit. 2002 Jan-Feb;15(1):6-18.
Functional characterization of an anti-estradiol antibody by site-directed mutagenesis and molecular modelling: modulation of binding properties and prominent role of the V(L) domain in estradiol recognition.

Coulon S, Pellequer JL, Blachere T, Chartier M, Mappus E, Chen Sw SW, Cuilleron CY, Baty D.

Institut de Biologie Structurale et de Microbiologie, 13402 Marseille Cedex 20, France.

The high-affinity monoclonal anti-estradiol antibody 9D3 presents a specificity defect towards estradiol-3-sulphate and 3-glucuronide conjugates incompatible with use in direct immunoassays. The corresponding single-chain variable fragment (scFv), cloned and produced in E. coli, exhibited a 10-fold lower affinity for estradiol (K(a)=1.2 x 10(9) M (-1)) and a slightly increased specificity defect for the 3-position. Site-directed mutagenesis revealed critical residues involved in estradiol recognition and produced mutants exhibiting up to a 3-fold increase of the binding affinity for estradiol and up to a 2-fold decrease of the cross-reactivity with estradiol-3-sulphate. A comparative model of the antibody 9D3-estradiol complex was built in which the estradiol D-ring is buried into the binding pocket while the 3-, 6- and 7-positions are solvent exposed, agreeing with the lack of specificity for these three positions. Two potential alternative orientations of the A-ring, one close to CDR H3 and L2 loops, and the other one close to CDR H2 and L3 loops, have been considered for the docking of estradiol, none of which could be unambiguously privileged taking into account data from cross-reactivity measurements, photolabelling and mutagenesis studies. For both orientations, estradiol is stabilized by hydrogen bonding of the 17beta-OH group with TyrL36, His89 and GlnH35 in the first case, or TyrL36, only, in the second case and by van der Waals contacts from TyrL91 with alpha- or beta-face of estradiol, respectively, and from ValH95 and GlyH97 with the opposite face. To elucid