FIGURE 7.

FoxO1 promotes atRA biosynthesis. HepG2 cells were infected with adenovirus 48 h prior to harvesting, incubated in growth or serum-free medium for 16 h, then treated with 50 nm (100 pmol) retinol in the final 4 h. Left, atRA synthesis is elevated in cells in serum-free medium. Dominant-negative FoxO1 (dnFoxO1) prevents the increase. Right, the amount of retinol recovered is elevated in cells incubated in serum-free medium: **, p < 0.005; ***, p < 0.0001 versus growth values; &, p < 0.05; &&, p < 0.005 as labeled; ns, not significantly different from growth medium.