High impact information on Cholestan-6-one, 3-hydroxy-, (3beta)-

• The dipole potential of phosphatidylcholine membranes was modified by incorporating into the bilayer the sterols phloretin and 6-ketocholestanol (KC), which decrease and increase the dipole potential, respectively [1].
• Increasing the content of cholesterol and 6-ketocholestanol (KC), which are known to increase psi D in the bilayer, results in an increase in the ratio, R, of the dye fluorescence excited at 440 nm to that excited at 530 nm in a lipid vesicle suspension; increasing the content of phloretin, which lowers psi D, decreases R [2].
• A quantitative analysis of the binding and translocation rate changes produced by ketocholestanol and phloretin is well accounted for by a point dipole model that includes a dipole layer due to phloretin or 6-ketocholestanol in the membrane-solution interface [3].
• The effects of the cholesterol analog 5 alpha-cholestan-3 beta-ol-6-one (6-ketocholestanol) on bilayer structure, bilayer cohesive properties, and interbilayer repulsive pressures have been studied by a combination of x-ray diffraction, pipette aspiration, and dipole potential experiments [4].
• 6-Ketocholestanol added to hepatocytes failed to counterbalance the uncoupling effect of thyroid hormones on delta psi(m) and respiration rate [5].

Biological context of Cholestan-6-one, 3-hydroxy-, (3beta)-

• Further studies on the recoupling effect of 6-ketocholestanol upon oxidative phosphorylation in uncoupled liver mitochondria [6].
• As it was reported on kidney mitochondrial membranes [Chavez et al. (1996) FEBS Lett. 379, 305-308], the recoupling effect caused by 6-ketocholestanol on submitochondrial particles and proteoliposomes could be due to a diminution of membrane fluidity [6].
• Phloretin and 6-ketocholestanol are penetration enhancers for percutaneous delivery of certain topically applied drugs [7].
• Inhibition of human polymorphonuclear leukocyte respiratory burst activity and aggregation by 6-ketocholestanol [8].
• Addition of phloretin, which is known to decrease the dipole potential drop, slows down the kinetics, whereas the addition of RH421 or 6-ketocholestanol, which increase the dipole potential drop, accelerates the kinetics [9].

Anatomical context of Cholestan-6-one, 3-hydroxy-, (3beta)-

• On the mechanism by which 6-ketocholestanol protects mitochondria against uncoupling-induced Ca2+ efflux [10].
• The effect of 6-ketocholestanol was studied on CCCP-induced uncoupling in liver mitochondria, submitochondrial particles and cytochrome oxidase proteoliposomes [6].
• The validity of the method was proved by treating hepatocytes with FCCP (decrease of Deltapsi) and subsequent addition of 6-ketocholestanol (increase of Deltapsi) [11].
• 6-Ketocholestanol is a recoupler for mitochondria, chromatophores and cytochrome oxidase proteoliposomes [12].
• 6-Ketocholestanol, a recoupler under these conditions, causes redistribution of Ca2+ from the cytosol into mitochondria [13].

Associations of Cholestan-6-one, 3-hydroxy-, (3beta)- with other chemical compounds

• The incorporation of 6-ketocholestanol also produces differential changes in the binding and translocation rates of hydrophobic ions, but in an opposite direction to those produced by phloretin [3].
• Phlorizin- and 6-ketocholestanol-mediated antagonistic modulation of alamethicin activity in phospholipid planar membranes [14].
• Phloretin and 6-ketocholestanol: membrane interactions studied by a phospholipid/polydiacetylene colorimetric assay and differential scanning calorimetry [15].
• Earlier we reported that some thyroid and steroid hormones and also 6-ketocholestanol used in micromolar concentrations modulated the effects of protonophoric uncouplers on isolated mitochondria (Starkov et al. (1997) Biochim. Biophys. Acta, 1318, 173-183) [16].

Analytical, diagnostic and therapeutic context of Cholestan-6-one, 3-hydroxy-, (3beta)-

• The effect of phloretin and 6-ketocholestanol on phase transition temperature and enthalpy was studied using differential scanning calorimetry [7].

References