50-28-2Relevant academic research and scientific papers
ANDROGEN METABOLISM IN MALE AND FEMALE BREAST TISSUE
Perel, E.,Davis, S.,Killinger, D. W.
, p. 345 - 352 (1981)
Incubation studies have been carried out using normal breast tissue and breast tissue from patients with gynecomastia, mammary dysplasia and breast carcinoma to determine the pattern of androstenedione metabolism.All tissues formed estrone (E1) and testosterone (T) in all incubations.Estradiol (E2) was isolated in incubations of tissue from 1 of 6 patients with mammary dysplasia, 5 of 6 patients with gynecomastia and in all incubations with normal and carcinoma tissue.Estrone formation was lowest in mammary dysplasia and gynecomastia, and higher in apparently normal breast tissue.The greatest E1 formation was found in incubations with breast carcinoma tissue, although there was considerable variation within this tissue group.Estradiol formation was low in all tissues, with the highest conversion rates in carcinoma tissue.Testosterone formation in carcinoma tissue was greater than in mammary dysplasia or gynecomastia, but similar to apparently normal tissue.These results indicate that breast tissue from different pathological states varies in its capacity to aromatize androstenedione (A) to estrogenic products and to convert it to other androgens.They have also shown that the pattern of metabolism is distinctive for the nature of the pathological abnormality.
Mechanism of action of bolandiol (19-nortestosterone-3β,17β-diol), a unique anabolic steroid with androgenic, estrogenic, and progestational activities
Attardi, Barbara J.,Page, Stephanie T.,Hild, Sheri A.,Coss, Christopher C.,Matsumoto, Alvin M.
, p. 151 - 161 (2010)
Bolandiol is a synthetic anabolic steroid that increases lean body mass and bone mineral density without significant stimulation of sex accessory glands in castrate adult male rats. Since bolandiol suppresses gonadotropins and endogenous testosterone (T) production, we investigated its mechanism of action. We compared the potency of bolandiol in vitro and in vivo with T, 5α-dihydrotestosterone (DHT), 19-nortestosterone (19-NT) and estradiol (E2). Bolandiol bound with lower affinity to the recombinant rat androgen receptor (AR) than the other androgens and had low, but measurable, affinity for recombinant human progestin receptors (PR-A, PR-B), and estrogen receptors (ERα and β-1). Functional agonist activity was assessed in transcription assays mediated by AR, PR, or ER. Bolandiol was stimulatory in all these assays, but only 4-9% as potent as T, DHT, and 19-NT via AR, 1% as potent as progesterone via PR, and 3% and 1% as potent as E2 acting through ERα or ERβ, respectively. In immature castrate rats, bolandiol was equipotent to T in stimulating growth of the levator ani muscle but less potent than T in stimulating growth of the sex accessory glands. Bolandiol also stimulated uterine weight increases in immature female rats, which were partly blocked by ICI 182,780, but it was not aromatized in vitro by recombinant human aromatase. In contrast to T, stimulation of sex accessory gland weights by bolandiol was not inhibited by concomitant treatment with the dual 5α-reductase inhibitor dutasteride. As bolandiol exhibits tissue selectivity in vivo, it may act via AR, PR, and/or ER, utilize alternative signaling pathway(s) or transcriptional coregulators, and/or be metabolized to a more potent selective steroid.
Substrate specificity of the placental microsomal aromatase
Gibb,Lavoie
, p. 507 - 519 (1980)
Using an accurate and sensitive assay for the human placental aromatase we apparent found apparant Km values for androstenedione (4-androstene-3, 17-dione) and testosterone to be 14 ± 4.0 nM and 41 ± 12 nM respectively. These values were significantly different (p 0.001). Analyses at substrate concentrations 5-10 fold above and below the Km values did not indicate any anomalous kinetic behavior. Mixed substrate experiments were consistent with a single enzyme metabolizing both steroids; each competitively inhibited the aromatization of the other, and the 'Ki' values were the same as their apparent Km values. Sodium chloride (1.2M) significantly increased the rate of testosterone aromatization by decreasing its Km value and had no significant effect on the aromatization of androstenedione. However, in the presence of this salt testosterone still inhibited the aromatization of androstenedione competitively with a 'Ki' equal to its apparent Km. Our data is therefore consistent with the proposal that human placental microsomes contain a single 'high affinity' site for the aromatization of androstenedione and testosterone.
Aldo-keto reductase 1C3 expression in MCF-7 cells reveals roles in steroid hormone and prostaglandin metabolism that may explain its over-expression in breast cancer
Byrns, Michael C.,Duan, Ling,Lee, Seon Hwa,Blair, Ian A.,Penning, Trevor M.
, p. 177 - 187 (2010)
Aldo-keto reductase (AKR) 1C3 (type 5 17β-hydroxysteroid dehydrogenase and prostaglandin F synthase), may stimulate proliferation via steroid hormone and prostaglandin (PG) metabolism in the breast. Purified recombinant AKR1C3 reduces PGD2 to 9α,11β-PGF2, Δ4-androstenedione to testosterone, progesterone to 20α-hydroxyprogesterone, and to a lesser extent, estrone to 17β-estradiol. We established MCF-7 cells that stably express AKR1C3 (MCF-7-AKR1C3 cells) to model its over-expression in breast cancer. AKR1C3 expression increased steroid conversion by MCF-7 cells, leading to a pro-estrogenic state. Unexpectedly, estrone was reduced fastest by MCF-7-AKR1C3 cells when compared to other substrates at 0.1 μM. MCF-7-AKR1C3 cells proliferated three times faster than parental cells in response to estrone and 17β-estradiol. AKR1C3 therefore represents a potential target for attenuating estrogen receptor α induced proliferation. MCF-7-AKR1C3 cells also reduced PGD2, limiting its dehydration to form PGJ2 products. The AKR1C3 product was confirmed as 9α,11β-PGF2 and quantified with a stereospecific stable isotope dilution liquid chromatography-mass spectrometry method. This method will allow the examination of the role of AKR1C3 in endogenous prostaglandin formation in response to inflammatory stimuli. Expression of AKR1C3 reduced the anti-proliferative effects of PGD2 on MCF-7 cells, suggesting that AKR1C3 limits peroxisome proliferator activated receptor γ (PPARγ) signaling by reducing formation of 15-deoxy-Δ12,14-PGJ2 (15dPGJ2).
INHIBITION OF ESTROGEN SYNTHESIS IN HUMAN BREAST TUMORS BY TESTOLOLACTONE AND BROMOANDROSTENEDIONE
Budnick, Rose Marie,Dao, Thomas L.
, p. 533 - 542 (1980)
The inhibition of aromatase enzyme in human breast tumors by Δ1-testololactone, testololactone, 6α-bromoandrostenedione, and 6β-bromoandrostenedione was investigated.Estrone and estradiol synthesis from androstenedione was reduced in 3 tumor incubations by the presence of 0.13 mmol Δ1-testololactone and testololactone. 6α- and 6β-bromoandrostenedione (2.0 μM) were also shown to block estrogen synthesis in 2 tumors.Furthermore, Lineweaver-Burk plots revealed that all 4 compounds are competitive inhibitors of androstenedione aromatization.An apparent Km of the aromatase enzyme for androstenedione of 0.08 μM and a Vmax of 23 pmol of estrone synthesized/g tumor/hr were determined for one human breast tumor specimen.These results demonstrate that these aromatase inhibitors may be useful for the treatment of breast cancer.
Complexation of steroid hormones with cyclodextrin derivatives: Substituent effects of the guest molecule on solubility and stability in aqueous solution
Albers,Muller
, p. 756 - 761 (1992)
The inclusion complexation of homologous derivatives of steroid hormones with cyclodextrins and 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD) was investigated with regard to underlying structure-interaction relationship. The interaction was studied by phase solubility analysis and stabilization effects of complex formation with 2-HP-β-CD. The solubilizing and stabilizing abilities of 2-HP-β-CD were generally more effective for testosterone derivatives than for estradiol esters. Within a homologous series of steroid hormones, the steepest linear solubility isotherms were found for 17-methyl and 3-methyl derivatives. The solubilization of steroid esters by 2-HP-β-CD depended on the structure and length of the ester side chain. The interaction of 2-HP-β-CD with the steroids was hindered by long- chain fatty acid ester groups. With increasing length of the side chain, a decline of the isotherms occurred and the phase solubility behavior changed from linear to exponential. Contrary to expectations, benzoylation of steroids considerably decreased the guest-host interaction. The observed rates of degradation of the steroid esters were significantly reduced by 2- HP-β-CD, depending on the chain length, and correlated well with the order found in phase solubility analysis. The degradation showed no deviations from pseudo-first-order kinetics, and the degradation mechanism was not changed because of complexation. The results suggest that interaction of 2-HP-β-CD with steroid esters involves the ester functions of the prodrugs and is more suitable for unsubstituted guest molecules.
Thermodynamic Meerwein-Ponndorf-Verley reduction in the diastereoselective synthesis of 17α-estradiol
Ahmed, Gulzar,Nickisch, Klaus
, p. 1 - 4 (2016)
The synthesis of 17α-hydroxy steroids generally requires multiple synthetic manipulations. The synthesis of 17α-estradiol is no exception, as this process involves the protection and release of the 3-hydroxy functional group. The diastereoselective reduction of the 17-keto-steroid can be utilized to prepare 17α-hydroxy-steroids. Here, 17α-estradiol was synthesized from commercially available estrone under thermodynamic Meerwein-Ponndorf-Verley (MPV) conditions in a single step, followed by simple chromatographic separation over silica gel. The remaining mixture of unreacted estrone and estradiols was easily recycled through Oppenauer oxidation to estrone, with an overall yield of 68% 17α-estradiol.
177. The Enantioselective Synthesis of (+)-Estradiol from 1,3-Dihydrobenzothiophene-2,2-dioxide by Successive Thermal SO2-Extrusion and Cycloaddition Reactions
Oppolzer, Wolfgang,Roberts, David Anthony
, p. 1703 - 1705 (1980)
The optically pure steroid (+)-15 has been synthesized from the easily accessible (+)-carboxylic acid 11 by a sequence of 7 steps in 50percent overall yield.The key steps are the regioselective deprotonation/alkylation 7+13->14 and the thermal SO2-extrusion/cycloaddition 14->15 (Scheme 3).The compound (+)-15 has been readily converted to the naturally occurring (+)-estradiol (17) in 60percent yield.
Estramustine binding in rat, baboon and human prostate measured by high pressure liquid chromatography
Kirdani,Corrales,Hoisaeter,Karr,Murphy,Sandberg
, p. 471 - 484 (1981)
High pressure liquid chromatography (HPLC) was used to determine 3H-estramustine (estradiol-17β3N-bis-[2-chlorethyl] carbamate), 3H-17β-hydroxy-5α-androstan-3-one (3H-dihydrotestosterone or 3H-DHT), 3H-estradiol-17β (3H-E2) and 3H-3β-hydroxy-5-pregnen-20-one (3H-pregnenolone) binding in 50μl of cytosol utilizing a column which separates proteins in the molecular weight range of 2,000 to 70,000 daltons. The rat prostate contains a protein in considerable concentration and with the highest affinity for estramustine (375,000dpm 3H-estramustine per mg. cytosol protein) among the substances tested. Operationally, we have named this protein 'estramustine binding protein' (EBP), though it is very likely similar to other previously described prostatic proteins (e.g., α-protein, prostatein, prostatic binding protein). The sensitivity of the HPLC method disclosed EBP-like proteins, but in much lesser concentrations, in some of the other tissues tested. The concentration of these proteins in the human and baboon prostates was much lower (average for the baboon cranial lobe 4800dpm/mg cytosol protein, with a somewhat higher value for the caudal lobe) than that in the rat gland. The amount of the EBP-like protein was higher in prostatic cancer than in that of benign prostatic hypertrophy (BPH) (range 9350 - 25,900 vs. 2200 - 18,900 dpm/mg cytosol protein). In the human, the highest value was found in one normal prostate tested (106,000 dpm/mg) cytosol protein).
Purification and characterization of aromatase from human placenta
Hall, Peter F.,Chen, Shiuan,Nakajin, Shizuo,Shinoda, Masato,Shively, John E.
, p. 37 - 50 (1987)
Aromatase from human placenta has been purified to homogeneity (MW 55000).Enzymatic activity can be reconstituted with reductase from pig liver in an aqueous buffer or after incorporation of the enzyme into liposomes.In both cases the enzyme converts androstenedione to estrone and testosterone to estradiol.Aromatase shows a typical CO-spectrum when reduced with dithionite and a type I spectral shift with both substrates.The NH2 terminal amino acid sequence is hydrophobic but shows no homology to that of other cytochromes P-450.Five cysteine peptides have been isolated by HPLC following tryptic digestion of the -carboxymethylated protein.Amino acid sequence of these peptides reveal that histidine is the carboxy-terminal amino acid of the protein and that significant homology exists with corresponding peptides from other cytochromes P-450.Unique oligonucleotides (62 and 30 MER) synthesized on the basis of a 45 amino acid sequence near the center of the molecular have been used to clone the aromatase gene from a cDNA expresssion library from human placenta in λgt11.
