24(S),25-Epoxycholesterol. Evidence consistent with a role in the regulation of hepatic cholesterogenesis.
Chromatography-High-Pressure-Liquid, Human, Hydroxymethylglutaryl-CoA-Reductases: ai, Liver: an, me, SUPPORT-U-S-GOVT-P-H-S
J-Biol-Chem. 1985 Nov 5; 260(25):13391-4.
HL23083, CA02758, HL05360
Previously we showed that 24(S),25-epoxycholesterol is formed from acetate, via squalene 2,3(S),22(S),23-dioxide and 24(S),25-oxidolanosterol, during the normal course of cholesterol biosynthesis in S10 rat liver homogenate (Nelson, J. A., Steckbeck, S. R., and Spencer, T. A. (1981) J. Biol. Chem. 256, 1067-1068; Nelson, J. A., Steckbeck, S. R., and Spencer, T. A. (1981) J. Am. Chem. Soc. 103, 6974-6975). Herein we demonstrate that the nonsaponifiable extract from human liver tissue contains 24(S),25-epoxycholesterol in an amount approximately 10(-3) relative to cholesterol. We show that 24(S),25-epoxycholesterol, like many other oxygenated sterols, represses hydroxymethylglutaryl-CoA reductase activity in cultured cells and binds to the cytosolic oxysterol-binding protein. Furthermore, we show that this epoxide is not rapidly metabolized in cultured cells. These results suggest that 24(S),25-epoxycholesterol may participate in the regulation of hepatic cholesterol metabolism in vivo.
Spencer, T A.; Gayen, A K.; Phirwa, S; Nelson, J A.; Taylor, F R.; Kandutsch, A A.; and Erickson, S K., " 24(S),25-Epoxycholesterol. Evidence consistent with a role in the regulation of hepatic cholesterogenesis." (1985). Faculty Research 1980 - 1989. 686.