The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The analysis of stress-induced changes in the brain neurosteroid levels by liquid chromatography (LC)–electron capture atmospheric pressure chemical ionization-mass spectrometry (ECAPCI-MS) is described. In the present method, neurosteroids were derivatized with a highly electron-affinitive reagent, 2-nitro-4-trifluoromethylphenylhydrazine (NFPH), to convert them to the corresponding hydrazones. The...
Traditionally, steroid hormone effects have been described as a result of the modulation of nuclear transcription, thus triggering genomic events that are responsible for physiological effects. Despite early observations of rapid steroid effects that were incompatible with this theory, nongenomic steroid effects have been widely recognized only recently. However, the nongenomic effect of glucocorticoid...
Fifteen steroids were isolated from the soft coral Dendronephthya sp., of which five are determined as new compounds, namely (22E)-3-O-β-formylcholest-5,22-diene (1), (22E)-3-O-β-formyl-24-methyl-cholest-5,22-diene (2), 2-ethoxycarbonyl-2-β-hydroxy-A-nor-cholest-5-ene-4-one (3), (22E)-2-ethoxycarbonyl-2-β-hydroxy-A-nor-cholest-5,22-diene-4-one (4), and (22E)-2-ethoxycarbonyl-2-β-hydroxy-24-mthyl-A-nor-cholest-5,22-diene-4-...
New polyhydroxylated sterols, stylisterol A–C (1–3), and a novel 5,19-cyclosterol, hatomasterol (4) were isolated from the Okinawan sponge Stylissa sp. Structural determinations of these compounds were made by spectroscopic analysis and chemical conversion. Assessment of cytotoxicity toward HeLa cells was also determined.
Calcitriol and some of its analogs have antiproliferative activity, but at the same time, can cause resistance to apoptosis induced by known cytostatic drugs. In this paper, we examined the effects of treatment with calcitriol or its side-chain-modified analogs, analog of Vitamin D 2 , coded PRI-1906, with monohomologated and unsaturated side-chain and the analog of Vitamin D 3 , coded...
Starting from D-seco derivatives of 5-androstene 1–3, the D-homo lactones, 4 and 5, were synthesized. By the Oppenauer oxidation and/or by dehydration of 4 and 5 with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil), the corresponding D-lactones 6–12 were obtained. The structures of 6 and 10 were unambiguously proved by the appropriate X-ray structural...
A variety of evidence has been obtained that estrogens are weak tumor initiators. A major step in the multi-stage process leading to tumor initiation involves metabolic formation of 4-catechol estrogens from estradiol (E 2 ) and/or estrone and further oxidation of the catechol estrogens to the corresponding catechol estrogen quinones. The electrophilic catechol quinones react with DNA mostly...
The nonsteroidal synthetic estrogen hexestrol (HES), which is diethylstilbestrol hydrogenated at the C-3–C-4 double bond, is carcinogenic. Its major metabolite is the catechol, 3′-OH-HES, which can be metabolically converted to the catechol quinone, HES-3′,4′-Q. Study of HES was undertaken with the scope to substantiate evidence that natural catechol estrogen-3,4-quinones are endogenous carcinogenic...
The first synthesis of 16,16,20,20,20-pentadeuterio-3′-hydroxystanozolol (8) in 26% yield over nine steps is described using moderately priced starting materials and economic amounts of reagents. Compound 8 can be used as an internal standard in screening procedures for anabolic steroids as well as for the quantification of stanozolol metabolites via mass spectrometric techniques, such as LC–MS or...
Sex steroid inhibitors were used to characterize the effects of 17β-estradiol (E2) and testosterone (T) on the sexual growth dimorphism of Eurasian perch juveniles. In experiment 1, growth responses to different doses of either E2 (25, 50, 75, and 100mgkgdiet−1) or fadrozole (Fa; 50 and 100mgkgdiet−1) were compared in triplicate tanks of 30 fish each during 85 days. In experiment 2, five diets containing...
Aim of the study is to compare the effects of preoperative therapy with tibolone plus gonadotropin-releasing hormone analogue (GnRH-a) in premenopausal women with those of GnRH-a alone on clinical response, uterine volume, immunohistochemical expression of platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) and vascular features...
High-intensity ultrasound (HIU) and microwave (MW) irradiation, having emerged as effective promoters of organic reactions, were exploited for the synthesis of bile acids derivatives. Esterification, amidation, hydrolysis, oxidation, and reduction were investigated. Compared to conventional methods, both techniques proved much more efficient, increasing product yields and dramatically cutting down...
Two new steryl esters with a polyhydroxylated ergostane-type nucleus, 3β,5α-dihydroxy-(22E,24R)-ergosta-7,22-dien-6β-yl oleate (1) and 3β,5α-dihydroxy-(22E,24R)-ergosta-22-en-7-one-6β-yl oleate (2), were isolated from the fruiting bodies of the basidiomycete Tricholomopsis rutilans along with three known sterols (3, 4, and 5). The structures of compounds 1 and 2 were established on the basis of spectroscopic...
In a previous report, it was demonstrated that the 3-carbonyl of androsta-1,4-dien-3,17-dione (ADD) can be selectively protected with 2-(methylamino)benzethiol in the presence of BF 3 in good yield. We explored the applicability of this method for other 1,4-dien-3-one steroids and got the desired protective products in different yield. Other than the usual protected products, we also got some...
The stereochemistry of the addition of methylmagnesium bromide to a steroidal 4,5-epoxy-3-ketone has been shown to be determined by the stereochemistry of the epoxide. The epoxidation to the corresponding 3-alkyl-3-hydroxy-4-enes by per-acid was determined by the stereochemistry of the allylic alcohol.
This study describes an oral administration of 5mg of [1,2,4,19- 13 C 4 ,11α- 2 H]cortisol (cortisol- 13 C 4 , 2 H 1 ) to a human subject performed on two separate occasions, one with cortisol- 13 C 4 , 2 H 1 alone and the other with cortisol- 13 C 4 , 2 H 1 plus 130mg per day of...
Specific A-ring hydroxylated metabolites of 17β-estrogens are known to be endogenous pro-carcinogens, more particularly the 4-hydroxylated forms of estrogens produced by cytochrome P4501B1. In this study, we investigated whether estradiol-17α, the main hepatic residue of estradiol-17β in cattle treated for anabolic purposes with estradiol containing implants, could be significantly metabolized by...
Fibroadenomas are the most common benign lump in females. The study of gene alterations and/or deregulation in reproductive years may help explain hormonal physiological processes involved in nodule development and evolution. The objective was to compare ER-α, c-myc, and bcl-2 gene expression in breast fibroadenomas and in normal tissue and evaluate menstrual cycle, parity, and oral contraceptive...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.