Deiodinases in Human Adipose Tissue from Obese Patients. Differences by Gender and Anatomical Depot

T3 regulates energy metabolism, glucose and lipid metabolism and several markers of adipocyte differentiation in white adipose tissue (WAT). T3 levels in tissues are regulated by the deiodinases (D1, D2, D3 or DIO1, DIO2, DIO3, respectively). Aim: To analyze DIO1, DIO2 and DIO3 deiodinases activity and mRNA expression and T4 and T3 concentrations in omental (OM) and subcutaneous (SC) WAT from obese, evaluating the differences by gender and anatomical depot. DIOs mRNAs were also analyzed in lean versus obese subjects. Results: In obese patients, T4 was lower only in SC WAT from obese men and T3 was lower in OM and SC WAT from obese women. In agreement, D2 activity was lower in SC WAT from obese women while D3 activity tended to increase in OM an SC WAT from obese women, explaining the lower T3 in WAT. The highest T3 was found in OM WAT from obese men together with the lowest D3 activity. DIO1 and DIO2 mRNA were higher in the SC WAT from both obese men and women. DIO1 and DIO3 mRNA were increased in OM and SC WAT from obese vs lean patients. DIO2 mRNA increased only in OM from IR-Obese and was always higher in SC than in OM WAT. DIO2 mRNA is higher in OM floating adipocytes and DIO3 mRNA in the stromal vascular fraction. Conclusion: In Conclusion gender and depot differences were observed in the three deiodinases studied, both in activity and mRNA expression.