Low‐Dose Dihydrotestosterone Lowers Lipogenic Master Regulator in Liver and Adipose Tissue from Female Mice
Authors: Myer Jessica Grace 
Published: April 2020

Polycystic Ovarian Syndrome (PCOS) is the leading cause of infertility among women caused by high androgen levels and affects 1 in 10 women. Due to the premature use of hormonal birth control, a large population of women are unaware they have symptoms of PCOS. Non‐Alcoholic Fatty Liver Disease is a continuum of inflammation that limits the livers ability to function properly.

Lean hyperandrogenic (HA) women who are diagnosed with PCOS have been associated to also have insulin resistance (IR) and Non‐Alcoholic Fatty Liver Disease (NAFLD). We hypothesized that low dose (dihydrotestosterone) DHT would interrupt hepatic lipid metabolism leading to NAFLD. Proving that the HA and HFD induced insulin resistance pathways are connected would be beneficial for the lives of women with Type 2 Diabetes and PCOS, as it could aid in early screening and detection for NAFLD.

We used a low dose DHT animal model to induce the PCOS symptoms onto the mice. Protein concentration assay was run on the liver, adipose, and skeletal muscle tissues using bicinchoninic acid (BCA) protein assay. Proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and transferred to nitrocellulose membranes to be prepared for Western blot analysis. They were blocked then incubated with primary antibodies (SREBP1, SREBP2, p‐ACC, ACC, and FAS; 1:1000 dilution), using GAPDH as a loading control. After incubation with secondary antibodies (goat anti‐mouse IgG; 1:5000 dilution), enhanced chemiluminescence was used for detection of proteins. Densities were quantified using myImageAnalysis software and analyzed by two‐tailed t‐tests with Prism software.

The increased hepatic lipid content of DHT mice signifies that the low dose DHT causes NAFLD. Low dose DHT mice displayed decreased inactive and active forms of cytosolic SREBP1c and increased levels of FAS. Inactive and active forms of SREBP2 and p‐ACC levels were the same in control and DHT mice. Low dose DHT lowered the active form of SREBP1c but not the inactive form in WAT compared to controls. In comparison to the controls, p‐ACC was decreased in low dose DHT mice. FAS and the inactive and active form of SREBP2 were unaltered in low dose DHT mice compared to controls. ChREBP protein levels were not readily detected and unchanged in WAT tissue of low dose DHT mice compared to controls. ASCVL1 (FATP2) protein expression was increased in WAT of low dose DHT mice. PPARy was unchanged in WAT of low dose DHT mice compared to controls. FXR protein levels were trending towards being increased but were not significantly different in WAT of low dose DHT mice compared to controls. Visfatin protein levels were not readily detected or altered in WAT tissue of low dose DHT mice compared to controls.

Overall, the findings suggest that low‐dose DHT is causing the translocation of SREBP‐1 from the cytosol into the nucleus leading to increased lipogenic gene expression. Low‐dose DHT does not affect overall lipogenic gene expression in skeletal muscle of female mice. Future studies may focus on nuclear extraction to isolate key nuclear proteins (SREBP‐1, SREBP‐2) in order to see whether they are translocated to the nucleus.

Support or Funding Information

Funded by the APS STRIDE Fellowship and Howard University Faculty Start up funds. Preliminary data collection and analysis completed by Tina Seidu, Patrick McWhorter, Rabita Alamgir, and Dilip Bogle.

Low‐dose DHT (a mouse model of lean PCOS) caused NAFLD.

Figure 1