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1.
The formation of cholest-5-ene-3β,26-diol as an intermediate in the conversion of cholesterol into bile acids by liver mitochondria 下载免费PDF全文
K. A. Mitropoulos M. D. Avery N. B. Myant G. F. Gibbons 《The Biochemical journal》1972,130(2):363-371
1. When [(14)C]cholesterol was incubated with rat liver mitochondria, radioactive 26-hydroxycholesterol, 3beta-hydroxychol-5-enoic acid and other bile acids were isolated from the incubation mixture. 2. In the absence of added 26-hydroxycholesterol, the specific radioactivity of the 26-hydroxycholesterol formed from [(14)C]cholesterol during the incubation was higher than that of the 3beta-hydroxychol-5-enoic acid. Addition of increasing amounts of 26-hydroxycholesterol led to a progressive fall in the specific radioactivity, and to a progressive increase in the mass, of the 3beta-hydroxychol-5-enoic acid recovered at the end of the incubation. 3. It is concluded that 26-hydroxycholesterol is an intermediate in the formation of 3beta-hydroxychol-5-enoic acid from cholesterol. 4. Comparison of the specific radioactivity of the 26-hydroxycholesterol formed in the incubation mixture with that of the added [(14)C]cholesterol indicates that endogenous cholesterol in mitochondria is accessible to cholesterol 26-hydroxylase. 相似文献
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《Steroids》2014
Women with polycystic ovary syndrome (PCOS) show high prevalence of endometrial hyperplasia and adenocarcinoma. Endometrial proliferation is increased, evaluated by high levels of Ki67 (cell cycle marker) and low levels of p27 (negative regulator of cell cycle). Nevertheless, endometrial changes in cyclin D1 (positive regulator of cell cycle) in PCOS-women are not described. Androst-5-ene-3β,17β-diol (androstenediol), steroid with estrogenic activity present in endometria, could be related to increased endometrial cell proliferation. The objective of this study was to determine protein content of cyclin D1 and androstenediol levels in endometria from PCOS and control-women and to evaluate the possible mechanism favoring cell proliferation associated with hormonal characteristics of patients. Therefore, cyclin D1 protein content in PCOS-women and control-endometrial tissue were assessed by western blot and immunohistochemistry. The androstenediol levels were evaluated by ELISA. To further analyze the effect of steroids (androstenediol, 17β-estradiol, testosterone) in cell proliferation, levels of proteins cyclin D1, p27 and Ki67 were evaluated in an in vitro model of stromal endometrial cells T-HESC and St-T1b. An increase in cyclin D1 and androstenediol was observed in tissues from PCOS-women relative to control group (p < 0.05). In the in vitro model, androstenediol exerted increase in cyclin D1 (p < 0.05) and a decrease in p27 protein level (p < 0.05), while Ki67 in St-T1b cells increased under this stimulus (p < 0.05). Testosterone produces opposite effects in the levels of the above markers (p < 0.05). Therefore, the hormonal imbalance associated with this syndrome could alter endometrial tissue homeostasis, promoting cell proliferation. Androstenediol is a molecule that could be involved by stimulating proliferation, whereas testosterone elicits a role of cell cycle repressor. 相似文献
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The potent anti-inflammatory activity of exogenous dehydroepiandrosterone (DHEA) in rodents has not translated to humans. This disparity in pharmacological effects has been attributed to factors such as differences in expression and function of molecular targets and differential metabolism. Hepatocytes from rats, dogs, monkeys, and humans were used to measure species-specific metabolism of a related compound, androst-5-ene-3β,17β-diol (5-AED) using reversed-phase radio-HPLC, to explore the metabolic contribution to this interspecies disparity. We found that rat hepatocytes transformed 5-AED predominantly into an array of highly oxidized metabolites. Canine metabolites overlapped with rat, but contained a greater abundance of less hydrophilic species. Monkey and human metabolites were strikingly less hydrophilic, dominated by 5-AED and DHEA conjugates. From the accumulating evidence indicating that the DHEA anti-inflammatory activity may actually reside in its more highly oxidized metabolites, we advance a hypothesis that the virtual absence of these metabolites in humans is central to the failure of exogenous DHEA to produce a potent pharmacological effect in clinical investigations. Accordingly, emulation of its anti-inflammatory activity in humans will require administration of an active native metabolite or a synthetic pharmaceutical derivative. 相似文献
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《Phytochemistry》1986,25(7):1745-1747
The structure of a new sesquiterpene diol from the liverwort Lepidozia reptans has been established as eudesm-3-ene-6β,7α-diol on the basis of its 1H and 13CNMR spectroscopic properties. 相似文献
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Recently, binding of 5-androsten-3β,17β-diol (Δ(5)-androstenediol) to human estrogen receptor-beta (ERβ) was found to repress microglia-mediated inflammation, which is associated with various neurodegenerative diseases, such as multiple sclerosis. In contrast, binding of estradiol to ERβ resulted in little or no repression of microglia-mediated inflammation. Binding of Δ(5)-androstenediol to ERβ, as well as to ERα, is unexpected because unlike estradiol, Δ(5)-androstenediol has a saturated A ring and a C19 methyl group. To begin to elucidate the interaction of Δ(5)-androstenediol with both ERs, we constructed 3D models of Δ(5)-androstenediol with human ERα and ERβ for comparison with the crystal structures of estradiol in ERα and ERβ. Conformational flexibility in human ERα and ERβ accommodates the C19 methyl on Δ(5)-androstenediol. This conformational flexibility may be relevant for binding of other Δ(5)-steroids with C19 methyl substituents, such as 25-hydroxycholesterol and 27-hydroxycholesterol, to ERs. 相似文献
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《Journal of steroid biochemistry》1982,16(2):225-230
Microsomal 5-ene-3β-hydroxysteroid dehydrogenase activity from fowl preovulatory granulosa tissue was solubilised by treatment with 2.0 M KCl. The efficiency of the solubilisation procedure was assessed by measuring the amount of activity remaining in the supernatant after centrifugation at 105,000 g for 8 h. The microsomal activity was resolved into two components: a fraction solubilised by the salt treatment and a fraction remaining membrane bound. The results indicate that the enzyme exists in two different environments within the membrane. The time course for the thermal inactivation of the microsomal enzyme supported this conclusion. The properties of the solubilised enzyme were compared with the untreated microsomal preparation, with respect to steroidal inhibition. Progesterone. 4-androstene-3,17-dione and oestradiol-17β all inhibited the enzyme and no difference was observed between the two preparations. The results are discussed in relation to the involvement of 5-ene-3β-hydroxysteroid dehydrogenase in the control of progesterone production in fowl granulosa tissue. 相似文献
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2,2′,4,4′-3H4-dihydrotigogenin was converted by Digitalis lanata plants into tigogenin. 相似文献
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Maud Voisin Sandrine Silvente-PoirotMarc Poirot 《Biochemical and biophysical research communications》2014
Cholesterol metabolism has been recently linked to cancer, highlighting the importance of the characterization of new metabolic pathways in the sterol series. One of these pathways is centered on cholesterol-5,6-epoxides (5,6-ECs). 5,6-ECs can either generate dendrogenin A, a tumor suppressor present in healthy mammalian tissues, or the carcinogenic cholestane-3β,5α,6β-triol (CT) and its putative metabolite 6-oxo-cholestan-3β,5α-diol (OCDO) in tumor cells. We are currently investigating the identification of the enzyme involved in OCDO biosynthesis, which would be highly facilitated by the use of commercially unavailable [14C]-cholestane-3β,5α,6β-triol and [14C]-6-oxo-cholestan-3β,5α-diol. In the present study we report the one-step synthesis of [14C]-cholestane-3β,5α,6β-triol and [14C]-6-oxo-cholestan-3β,5α-diol by oxidation of [14C]-cholesterol with iodide metaperiodate (HIO4). 相似文献
10.
Mode of formation of cholesta-5,7-dien-3β-ol from cholest-5-en-3β-ol by larvae of Calliphora erythrocephala 下载免费PDF全文
1. The conversion of cholest-5-en-3beta-ol (cholesterol) into cholesta-5,7-dien-3beta-ol by axenic Calliphora erythrocephala larvae was demonstrated. 2. The transformation is probably direct (Delta(5)-->Delta(5,7)) and does not involve a Delta(0) intermediate (Delta(5)-->Delta(0)-->Delta(7)--> Delta(5,7)). 3. Delta(7)-bond formation involves the stereospecific elimination of the 7beta hydrogen atom. 4. The relative amounts of free and esterified sterols were determined in larvae grown on cholesterol as sole sterol source and on 5alpha-cholestan-3beta-ol supplemented with minimal amounts of cholesterol. 5. The significance of the results is assessed in relation to the probable role of cholesta-5,7-dien-3beta-ol as an intermediate in the biosynthesis of ecdysones. 相似文献
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A single thin layer chromatography and three antibodies were used for the specific radioimmunoassay of four androgens in pooled rat plasma (Sprague-Dawley adult males). The following values were found (pg/ml ± SD). Testosterone : 3, 138 ± 173; dihydrotestosterone : 374 ± 20; 5α-androstane-3α 17β-diol : 284 ± 24; 5α-androstane-3β, 17β-diol : 223 ± 11. 相似文献
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《Journal of steroid biochemistry》1977,8(12):1253-1257
5α-androstane-3β,17β-diol was measured in human peripheral plasma using a specific antibody generated against a carboxymethyloxime BSA conjugate linked at position 7. Concentrations were significantly higher in normal men than women. Preliminary results suggest that plasma 5α-androstane-3β,17β-diol concentrations might be a useful clinical parameter in cases of hirsutism and male infertility. 相似文献
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《Journal of steroid biochemistry》1980,12(6):623-627
Five alpha-androstane-3α,17β-diol (3α-diol) an active metabolite of testosterone (T) was measured in the spermatic and peripheral venous blood of 6 normal males using mass-fragmentography. Using this method 3α-diol was clearly separated from the following isomers: 5α-androstane-3β,17β-diol, 5β-androstane-3α,17β-diol and 5β-androstane-3β,17β-diol. The mean concentrations (±SE) of 3α-diol in spermatic and peripheral venous blood were respectively 100 ± 38 ng/100 ml and 7.7 ± 1.9 ng/100 ml. The existence of a significant (P < 0.01) gradient between spermatic and peripheral vein clearly demonstrates that the human testis secretes 3α-diol. 相似文献
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The 4,4-dimethylsterols 4α-lanost-24-ene-3β,9α-diol-[2-3H2] and parkeol-[2-3H2] were synthesized from lanosterol and subsequently incubated with cultures of Ochromonas malhamensis. 5α-Lanost-24-ene-3β,9α-diol was converted into poriferasterol with three times the efficiency of parkeol. Clionasterol was also found to be labelled from both parkeol and 5α-lanost-24-ene-3β,9α-diol. No significant incorporation of radioactivity into sterols was obtained after feeding 5α-lanost-24-ene-3β,9α-diol to higher plants, the chlorophyte alga Trebouxia, yeast or a cell free homogenate of rat liver. 相似文献
15.
Fluorescence studies of protein–sterol relationships in human plasma lipoproteins (Short Communication) 下载免费PDF全文
Cholesta-5,7,9(11)-trien-3beta-ol and its oleate ester were incorporated into human low-density lipoprotein and reconstituted high-density lipoprotein. The unesterified sterol was more efficient than its ester in quenching tryptophan fluorescence, especially in low-density lipoprotein. The results, which indicate that in such lipoproteins unesterified sterols are more closely associated with peptide than are esterified sterols, are used to assess possible structures for the lipoproteins. 相似文献
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Summary With growing cells of a Nocardia sp., isolated from soil, the degradation of 5-pregnene-3, 20-diol into 3-[5-oxo-7a-methyl-1 (1-hydroxo)-ethyl-3a-perhydroindane-4]-propionic acid was investigated. The results show that iron is essential for production of the perhydroindanpropionic acid, that this production is greatly enhanced by the presence of calcium and that it is maximal in the pH range 7.0–7.5.Abbreviations used in the text PD
5-pregnene-3, 20-diol (pregnendiol)
- PDSA
3-[5-oxo-7a-methyl-1(1-hydroxo)-ethyl-3a-perhydroindane-4]-propionic acid (pregnendiol-secoacid)
- PSA
3-[5-oxo-7a-methyl-1-acetyl-3a-perhydroindane-4]-propionic acid (progesterone-secoacid)
- EDTA
Ethylendiamintetracetic acid
- DMSO
Dimethylsulfoxide 相似文献
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Bernard Overdijk Elly F J Hiensch-Goormachtig Edvard P Beem Gé J Van Steijn Leo A W Trippelvitz Jan J W Lisman Herman Van Halbeek Johanna H G M Mutsaers Johannes F G Vliegenthart 《Glycoconjugate journal》1986,3(4):339-350
Acid -galactosidase (EC3.2.1.23) was obtained from human liver in a pure monomeric state (Mr63 000). The carbohydrate content of the enzyme was established to be, 9% by weight; mannose,N-acetylglucosamine, galactose andN-acetylneuraminic acid were found to be the constituent monosaccharides. The carbohydrate structures of the enzyme were studied at the glycopeptide level by employing 500 MHz1H-NMR spectroscopy, carbohydrate composition analysis and methylation analysis involving GLCMS. Based upon the intensities of relevant signals in the1H-NMR spectrum, approximately 60% of the chains were found to be of theN-acetyllactosamine type, having the structure
The rest appeared to be of the oligomannoside type (Man5-6GlcNAc2Asn). The carbohydrate composition and methylation analysis results sustained these findings, although the calculation of the distribution based upon these techniques indicated a somewhat lower percentage ofN-acetyllactosamine type chains. There are approximately three oligosaccharide chains per molecule. These findings offer an explanation for the abnormal distribution of -galactosidase in tissues and cultured fibroblasts of patients with I-cell disease. 相似文献
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Phytochemical studies on the leaves of Tripterygium wilfordii led to the isolation of seven new 18(4 → 3)-abeo-abietane lactones, triptergulides E – K (1 – 7). The structure of the new compounds was elucidated on the basis of their spectroscopic analysis, and the absolute configurations of compounds were confirmed by ECD, calculated ECD, and X-ray crystallographic analysis using anomalous scattering of Cu Kα radiation. Some compounds showed moderate inhibitory activities against NO, IL-6, and TNF-α production in LPS RAW 264.7 macrophage in vitro. 相似文献
20.
The effect of surfactant structure on ribonuclease A–surfactant interactions (Short Communication) 下载免费PDF全文
The enzymic activity of ribonuclease A was measured in the presence of several surfactants at pH7.2. Cationic surfactants with trimethylammonium and pyridinium head groups do not deactivate or denature the enzyme, whereas n-dodecylamine hydrochloride, like the anionic surfactant sodium n-dodecyl sulphate, deactivates and denatures ribonuclease A. 相似文献