Altered Hepatic Lipid Metabolism Contributes to Nonalcoholic Fatty Liver Disease in Leptin-Deficient Ob/Ob Mice

• Main Authors: James W. Perfield (Author), Laura C. Ortinau (Author), R. Taylor Pickering (Author), Meghan L. Ruebel (Author), Grace M. Meers (Author), R. Scott Rector (Author)
• Format: Book
• Published: Hindawi Limited, 2013-01-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 2090-0708; 2090-0716; 10.1155/2013/296537
• Keywords: Internal medicine; RC31-1245
• Source: Journal of Obesity, Vol 2013 (2013)

Nonalcoholic fatty liver disease (NAFLD) is strongly linked to obesity, insulin resistance, and abnormal hepatic lipid metabolism; however, the precise regulation of these processes remains poorly understood. Here we examined genes and proteins involved in hepatic oxidation and lipogenesis in 14-week-old leptin-deficient Ob/Ob mice, a commonly studied model of obesity and hepatic steatosis. Obese Ob/Ob mice had increased fasting glucose, insulin, and calculated HOMA-IR as compared with lean wild-type (WT) mice. Ob/Ob mice also had greater liver weights, hepatic triglyceride (TG) content, and markers of de novo lipogenesis, including increased hepatic gene expression and protein content of acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), and stearoyl-CoA desaturase-1 (SCD-1), as well as elevated gene expression of PPARγ and SREBP-1c compared with WT mice. While hepatic mRNA levels for PGC-1α, PPARα, and TFAM were elevated in Ob/Ob mice, measures of mitochondrial function (β-HAD activity and complete (to CO2) and total mitochondrial palmitate oxidation) and mitochondrial OXPHOS protein subunits I, III, and V content were significantly reduced compared with WT animals. In summary, reduced hepatic mitochondrial content and function and an upregulation in de novo lipogenesis contribute to obesity-associated NAFLD in the leptin-deficient Ob/Ob mouse.