In vivo cholesterol synthesis rates in the ABCG5/ABCG8 transgenic mice and wild-type controls. Four-month-old transgenic and control mice (n = 6 in each group) maintained on a chow diet were injected intraperitoneally with 40 mCi of [³H] water. The mice were sacrificed 1 hour later, and the tissues were collected and processed as described in Methods. *P < 0.05, **P < 0.01. This experiment was repeated, and the results were similar.