Figure 6. Restoration of PC synthesis in the absence of mTORC1 is sufficient to regulate TAG secretion in vivo.

Six- to ten-week-old Raptor^fl/fl animals were injected with either AAV-GFP (control, black) or AAV-CRE (L-Raptor–KO, white) and injected daily with saline (solid) or 150 mg/kg CDP-choline for 2 weeks. (A) Triglyceride secretion rates were determined in fasted animals by blocking triglyceride uptake via i.p. injection of poloxamer 407 and measuring the accumulation of triglyceride in the serum over time. n = 9–10. (B) Fasting serum triglyceride levels were measured. n = 9–10. (C) Fasting hepatic triglyceride levels were measured. n = 3. Isolated hepatocytes from treatment groups were cultured with ³H-glycerol ± CDP-choline (150 mg/kg) (D–G). (D) Secreted TAG was measured in the medium. n = 3. (E) Intracellular TAG was measured. n = 3. (F) Newly made secreted PC was measured in the medium. n = 3. (G) Intracellular newly made PC was measured. n = 3. For hepatocyte studies, hepatocytes from 3 mice were isolated and technical replicates pooled. Data represent 3 individual mice per condition. *P < 0.05; **P < 0.01 vs. control using 1-way ANOVA. ^†P < 0.01 using 1-way ANOVA.