Glucose tolerance test (GTT), pyruvate tolerance test, insulin tolerance test (ITT), and triglyceride clearance test were performed as previously described (17 (link)–19 (link)). Liver triglyceride extraction and quantification were performed at the UTSW Metabolic Phenotyping Core using a previously published protocol (17 (link)). Liver glycogen was extracted in water and assayed with a protocol provided in the Glycogen Colorimetric/Fluorometric Assay Kit from BioVision (catalog no. K646-100). Serum parameters (albumin, bilirubin, aspartate transaminase [AST], alanine transaminase [ALT], cholesterol, triglyceride, VLDL, LDL, and direct HDL) were measured and calculated with a VITROS analyzer (Ortho Clinical Diagnostics).