5α-Cholest-8(14)-en-3β-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 5α-cholest-8(14)-en-3β-ol-15-one (up to 40 μM). 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 μM 5α-cholest-8(14)-en-3β-ol-15-one incorporated almost seven times as much of the 15-ketosterol as K(15) cells incubated at 15 μM 15-kestosterol. Upon incubation of K(15) cells in lipid-rich medium containing 40 μM (2,4-\sp3H) 5α-cholest-8(14)-en-3β-ol-15-one, $\sim96\sp{14}$C) oleate (82 μM) 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.