Hormonal Regulation of Leptin, Resistin, and Plasminogen Activator Inhibitor-1 Gene Expression in 3T3-L1 Adipocytes

Abstract

Leptin, resisitn and PAI-1 (plasminogen activator inhibitor-1) are synthesized and secreted by rodent fat cells and recently postulated to be an important link to obesity. This study was conducted to characterize the hormonal regulation of leptin, resistin, and PAI-1 gene expression in the 3T3-L1 adipocytes. The cells were treated with 0.5 μM insulin, 1 μM dexamethasone (Dex), or 0.05 μM triiodothyronine (T3) for 72 hours. The mRNA levels of each peptide were measured by semi-quantitative RT-PCR. The mRNA level of the leptin-producing ob gene was significantly increased by insulin, Dex, and T3 by 3.2-, 3.1- and 2.7-fold, respectively, compared to the control (p＜0.05). The level of resistin mRNA was increased by insulin, Dex, and T3 by 2.7-, 2.5- and 2-fold, respectively, compared to the control (p＜0.05). Likewise, the level of PAI-1 mRNA was significantly increased by insulin, Dex, and T3 compared to the control (p＜0.05). Taken together, our results suggest that insulin, Dex, and T3 may regulate the gene expression of leptin, resistin, and PAI-1 in 3T3-L1 adipocytes.