Browsing by Author "Kirkpatrick, Nanda Duhe"

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    Metabolism of 5 alpha-cholest-8(14)-en-3 beta-ol-15-one in 15-ketosterol-adapted cells
    (1990) Kirkpatrick, Nanda Duhe
    5$\alpha$-Cholest-8(14)-en-3$\beta$-ol-15-one is a potent inhibitor of cholesterol biosynthesis in cultured cells. Cells derived from the CHO K-1 cell line have been isolated based on their ability to grow in high concentrations of 5$\alpha$-cholest-8(14)-en-3$\beta$-ol-15-one (up to 40 $\mu$M). These cells, designated as the 15-ketosterol-adapted or K(15) cells, accumulate cytoplasmic lipid-rich regions that appear as inclusions when observed by light microscopy. Results of studies presented herein show that K(15) cells incubated at 40 $\mu$M 5$\alpha$-cholest-8(14)-en-3$\beta$-ol-15-one incorporated almost seven times as much of the 15-ketosterol as K(15) cells incubated at 15 $\mu$M 15-kestosterol. Upon incubation of K(15) cells in lipid-rich medium containing 40 $\mu$M (2,4-$\sp3$H) 5$\alpha$-cholest-8(14)-en-3$\beta$-ol-15-one, $\sim$96% of the radioactivity recovered in an isolated floating lipid layer corresponded to 15-ketosteryl esters. Upon the addition of sodium (1-$\sp{14}$C) oleate (82 $\mu$M) to the incubation medium, the radioactivity recovered in the floating lipid layer corresponded to both 15-ketosteryl esters and triacylglycerols. Following removal of the 15-ketosterol from the growth medium, the K(15) cells excreted 66-88% of the incorporated 15-ketosterol into the medium.