Following 16 hrs of fasting, blood samples (n = 3) from each of the Abcg8+/+, Abcg8+/- and Abcg8-/- mice were collected from the retro-orbital venous plexus using heparinized capillary tubes under isoflurane anesthesia, and placed into precooled tubes containing 10 μl of 0.5 M EDTA. Equal volumes of plasma from each genotype were pooled and 100 μL of the pooled sample were injected and fractionated by fast protein liquid chromatography (FPLC) using a Superose 6 HR10/30 column (Pharmacia Biotech Inc., Piscataway, NJ, USA) and analyzed as described [27].