Descending Expression of miR320 in Insulin-Resistant Adipocytes Treated with Ascending Concentrations of Metformin.

: Some miRNAs are supposed to play a role in insulin resistance and metabolic disorders. Such miRNAs can be differentially expressed in response to a pharmacologic intervention for insulin resistance as a biomarker/risk factor for insulin resistance. This study aimed at determining the effect of Metformin on miR320 expression in insulin-resistant (IR) adipocytes. The 3T3L1 cells were expanded in DMEM, differentiated into adipocytes by differentiating medium, became resistant to insulin, and then were treated with ascending concentrations of Metformin. Quantitative real-time PCR was performed to profile the miR320 expression in 3T3L1 adipocytes, IR adipocytes, and Metformin-treated IR adipocytes. Compared to the normal adipocytes, IR adipocytes exhibited a significantly higher level of miR320 expression, however, in response to Metformin graded concentrations, IR adipocytes down-regulated miR320 and were almost at normal level. The maximum effect of Metformin was at 10 mM. In IR adipocytes, miR320 expression is over-expressed which can be down-regulated by Metformin treatment. The findings provide some information on a potentially new marker to determine insulin resistance and to predict response to insulin resistance therapy.