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Results for “Cholestadienes”

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At least 19 recordsLinked to original sources
PubMed2004

[Oxysterol (3,5-cholestadien-7-one, 5 beta-cholestan-3-one, 5,24-cholestadien-3 beta-OL) induced cytotoxicity and apoptosis in gallbladder epithelial cells].

BACKGROUND/AIMS: Biliary epithelial cells are exposed to highly concentrated oxysterols. Therefore, oxysterols may play a role in pathogenesis of biliary tract diseases. We investigated the cytotoxic effect and apoptosis inducing effect of oxysterol on gallbladder epithelial cells. METHODS: We studied the cytotoxic effect of 3,5- cholestadien-7-one, 5 beta-cholestan-3-one and 5,24-cholestadien-3 beta-OL which are identified in human bile and pigment gallstones on dog gallbladder epithelial cells (DGBE) and mouse gallbladder epithelial cells (MGBE). We used model bile to dissolve oxysterols as in vitro experiment and also used MTT, cell count, Diff-Quick stain, and flow cytometry to investigate cytotoxicity and apoptosis. RESULTS: Oxysterols dissolved in model bile have cytotoxic effects in a dose dependent fashion. In oxysterol containing model bile, viable cells are 51% in 500 microM 5 beta-cholestan-3-one (cholesterol:oxysterol 50:50) and 47% in 5 mM 3,5-cholestadien-7-one (90:10) on MGBE, and are 129% and 38% in 500 microM (50:50) 3,5-cholestadien-7-one and 5 beta-cholestan-3-one on DGBE, and are 74% and 71.5% in 5 mM (90:10) 3,5-cholestadien-7-one and 5 beta-cholestan-3-one on DGBE, respectively. 500 microM (50:50) 3,5- cholestadien-7-one, 5 beta-cholestan-3-one, and 5,24-cholestadien-3 beta-OL treated on DGBE increase the apoptotic cell number as 22.0+/-8.8, 30.2+/-12.6, and 45.5+/-13.2%, respectively, compared with control (14.6+/-10.0%). 500 microM (50:50) 3,5-cholestadien-7-one, 5 beta-cholestan-3-one, and 5,24-cholestadien-3 beta-OL also affect the changes in cell cycles compared with the control. CONCLUSIONS: We concluded that oxysterol containing model bile is useful as an in vitro experiment as model to analyze the effects of oxysterols on biliary epithelial cells and that adequate concentration of oxysterols can induce the cytotoxic effect and the apoptosis on gallbladder epithelial cells.

Animals↗
PubMed2005

Epoxidation and reduction of cholesterol, 1,4,6-cholestatrien-3-one and 4,6-cholestadien-3beta-ol.

Many naturally occurring polyhydroxylated sterols and oxysterols exhibit potent biologic activities. This paper describes reagent and position selectivity of epoxidation and reduction of cholesterol derivatives. Cholesterol was reacted with m-chloroperoxybenzoic acid (m-CPBA) to form 5alpha,6alpha-epoxycholestan-3beta-ol, but in reaction with 30% H(2)O(2), it did not reacted. 1,4,6-cholestatrien-3-one was obtained from cholesterol and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone in dioxane. 1,4,6-cholestatrien-3-one was reacted with 30% H(2)O(2) and 5% NaOH in methanol to give 1alpha,2alpha-epoxy-4,6-cholestadien-3-one, which was stereoselectively reduced with NaBH(4) to form 1alpha,2alpha-epoxy-4,6-cholestadien-3beta-ol and reduced with Li metal in absolute ethanol to give 2-ethoxy-1,4,6-cholestatrien-3-one. And 1,4,6-cholestatrien-3-one was epoxidized with m-CPBA in dichloromethane to afford 6alpha,7alpha-epoxy-1,4-cholestadien-3-one, which was reacted with NaBH(4) to synthesize 6alpha-hydroxy-4-cholesten-3-one and reduced Li metal in absolute ethanol to form 2-ethoxy-1,4,6-cholestatrien-3-one, respectively. 1,4,6-cholestatrien-3-one was reduced with NaBH(4) in absolute ethanol to form 4,6-cholestadien-3beta-ol, which was reacted with 30% H(2)O(2) to leave original compound, but was reacted with m-CPBA to give 4beta,5beta-epoxy-6-cholesten-3beta-ol as the major product and 4beta,5beta-epoxy-6alpha,7alpha-epoxycholestan-3beta-ol as the minor product.

Boron Compounds↗
PubMed1981

Synthesis of delta 5,22-cholestadien-3 beta-ol from delta 5,7,22-cholestatrien-3 beta-ol by a liver enzyme.

The rat liver enzyme system, which catalyzes reduction of delta 5,7,24-cholestatrien-3 beta-ol to cholesterol (delta 5-cholesten-3 beta-ol), converted radiolabeled delta 5,7,22-cholestatrien-3 beta-ol to delta 5,22-cholestadien-3 beta-ol, but not to cholesterol. This enzyme system thus contains membrane-bound delta 7- and delta 24-reductase and no delta 22-reductase. Kinetic and competition studies showed that the enzyme system contains a single delta 5,7-sterol delta 7-reductase, which is not influenced by unsaturation at the delta 22-position of the sterol side chain. The identity of delta 5,22-cholestadienol was established by chromatographic, spectral and chemical analyses. Use of the enzyme system and readily available delta 5,7,22-cholestatrienol provides a facile procedure for specific production of delta 5,22-cholestadien-3 beta-ol in quantity.

Animals↗
PubMed1970

Characterization of the structure of a 4-methyl-delta 8,24-cholestadien-3 beta-ol isolated from rat skin.

A new sterol has been isolated from the skin of rats treated with triparanol. Its chromatographic behavior on silicic acid-Celite columns and in gas-liquid chromatographic systems indicated it to be a 4-methyl-Delta(8,24)-cholestadien-3beta-ol. The specific rotation, the delayed color reaction with Liebermann-Burchard reagent, and the nuclear magnetic resonance (NMR) data support the Delta(8(9))-unsaturation. Previous workers have shown that triparanol treatment results in an accumulation of Delta(24)-unsaturated sterols in animal tissues. Consonant with this observation, the infrared, NMR, and mass spectrometric data confirm the presence of a C-24(25) unsaturated side chain in this sterol.

Animals↗