1846-P: Low-Dose Dihydrotestosterone Increased Lipogenic Proteins Resulting in Increased NAFLD via Regulation of SREBP1c in Liver Tissue of Normal Weight Female Mice

Hyperandrogenemia (HA) and insulin resistance are hallmarks of polycystic ovary syndrome (PCOS). These hallmarks are also integral elements of nonalcoholic liver disease (NALFD). Administering low dose dihydrotestosterone (DHT) induced a lean female mouse model with a PCOS-like phenotype. The molecular mechanism of HA-induced NAFLD has not been determined. We hypothesized that low dose DHT would interrupt hepatic lipid metabolism leading to NAFLD. We extracted white adipose tissue (WAT), liver, and skeletal muscle from control and low dose DHT female mice; and performed Western blot and real-time quantitative PCR (qRT-PCR) analysis of lipogenic intermediates. Low-dose DHT lowered the active form of cytosolic SREBP1 in the liver and WAT compared to controls. Additionally, low dose DHT increased inactive SREBP1 in the liver. However, DHT did not alter the levels of the active and inactive forms of SREBP2 in the liver and WAT. DHT increased SCAP protein expression and SCAP-SREBP1 binding, which helps activate SREBP. Regarding lipogenic enzymes, FAS mRNA and protein expression was increased in liver of DHT mice. p-ACC levels were unaltered in liver but decreased in WAT. Other lipid metabolism pathways were examined in liver and WAT but no changes were observed. Taken together, our findings support the hypothesis that cytosolic SREBP1 decreased due to its translocation to the nucleus, where it upregulated lipogenic mRNA expression. We showed that low-dose DHT increased SCAP-SREBP-1 association promoting the activation and translocation of SREBP1 from the cytosol to the nucleus to influence lipogenic gene expression leading to increased lipogenesis contributing to NAFLD.