Endogenously-produced 24,25EC correlates with cholesterol synthesis in different CHO cell-lines. (A) Various Chinese Hamster Ovary cell-types with different abilities to synthesise cholesterol were incubated in the presence of [1-14C]-acetate for 24 h. KEY: 1. CHO-7; 2. SRD-1; 3. M19; 4. SRD-13A; 5. 13A/pSCAP. For more details about these cell-lines, see . Neutral lipid extracts were separated by thin-layer chromatography and bands corresponding to authentic cholesterol and 24,25EC were visualized by phosphorimager and quantified by densitometry. Equations for the lines of best fit (B) y = 0.97x + 0.39; R2 = 0.89; P < 0.03. Values are means from 3 separate experiments set relative to CHO-7 cells which was assigned an arbitrary value of 1.