(A) Diets of age-matched male mice (n = 5–6/group, 10–15 weeks) were synchronized as described in the Methods. Plasma samples were obtained at the end of the last fasting period (Fasting) and then 4 hours after refeeding (Fed), and levels of TGs, nonesterified fatty acids (NEFAs) and (B) cholesterol were measured in duplicate (5 μL). Plasma glucose levels were measured from the first drop of blood from the tail vein. Values are shown as means (± SEM). The experiment was repeated and the data were similar. Groups were compared using 2-way ANOVA. *P < 0.05; **P < 0.01; ****P < 0.0001. The experiment was performed 3 times and the compiled results are shown. (C) The diets of the mice were handled as described in panel A. Four hours after refeeding, blood was collected from the WT mice. Mice were then injected with heparin intravenously (1 U/g), and blood was collected after 15 minutes. Pooled plasma was fractionated on a heparin column (1 mL) to separate hepatic lipase (HL) and LPL. TG lipase activity was measured in each fraction as described in Methods. Pooled plasma samples (10 μL) were diluted to 500 μL with PBS and incubated with heparin beads (20 μL) for 2 hours. The heparin bead–bound proteins were subjected to immunoblotting using anti-mouse LPL and HL polyclonal antibodies, as described in the Methods. Quantitative values are expressed as ratios to the level of HL and expressed relative to the WT value, which was set to 1.