Hydrogen sulfide (H2S) and inorganic polysulfides are important signaling molecules; however, little is known about their role in adipose tissue. We examined the effect of H2S and polysulfides on insulin sensitivity of the adipose tissue in rats. Plasma glucose, insulin, non-esterified fatty acids, and glycerol were measured after administration of H2S and the polysulfide donors, Na2S and Na2S4, respectively. In addition, the effect of Na2S and Na2S4 on insulin-induced glucose uptake and inhibition of lipolysis was studied in adipose tissue explants ex vivo. Na2S and Na2S4 administered in vivo at a single dose of 100 μmol/kg had no effect on plasma glucose and insulin concentrations. In addition, Na2S and Na2S4 did not modify the effect of insulin on plasma glucose, fatty acids, and glycerol concentrations. Na2S and Na2S4had no effect on the antilipolytic effect of insulin in adipose tissue explants ex vivo. The effect of insulin on 2-deoxyglucose uptake by adipose tissue was impaired in obese rats which was accompanied by lower insulin-induced tyrosine phosphorylation of IRS-1 and Akt. Na2S4, but not Na2S, improved insulin signaling and increased insulin-stimulated 2-deoxyglucose uptake by adipose tissue of obese rats. The results suggest that polysulfides may normalize insulin sensitivity, at least in the adipose tissue, in obesity/metabolic syndrome.
Keywords: adipose tissue; hydrogen sulfide; insulin sensitivity; obesity; polysulfides.