Identification of regulatory oxysterols, 24(S),25-epoxycholesterol and 25-hydroxycholesterol, in cultured fibroblasts.
Cattle, Cell-Line, Cholesterol: aa, bi, Chromatography-High-Pressure-Liquid, Chromatography-Thin-Layer, Cricetulus, Culture-Media, Enzyme-Repression, Fetus, Fibroblasts: me, Hamsters, Hydroxycholesterols: bi, ip, Hydroxymethylglutaryl-CoA-Reductases: bi, Lung, Mevalonic-Acid: me, SUPPORT-U-S-GOVT-P-H-S, Tritium
J-Biol-Chem. 1985 Nov 25; 260(27):14571-9.
Biosynthetically tritiated sterols from Chinese hamster lung (Dede) cells were fractionated by high performance liquid chromatography, and fractions were assayed for their ability to repress 3-hydroxy-3-methylglutaryl-CoA reductase in L cell cultures. Most of the activity found was associated with two oxysterols, 24(S),25-epoxycholesterol and 25-hydroxycholesterol. The identities of the two sterols were established by co-chromatography with authentic samples and by isotopic dilution and recrystallization. Only low levels of repressor activity were found in other fractions of the sterol extract. The endogenous concentrations of 24(S),25-epoxycholesterol (7.2 fg/cell) and 25-hydroxycholesterol (1.5 fg/cell) appear to be within the ranges required for the regulation of HMG-CoA reductase.
Saucier, S E.; Kandutsch, A A.; Taylor, F R.; Spencer, T A.; Phirwa, S; and Gayen, A K., " Identification of regulatory oxysterols, 24(S),25-epoxycholesterol and 25-hydroxycholesterol, in cultured fibroblasts." (1985). Faculty Research 1980 - 1989. 685.