Effect of Exogenous Hydrogen Sulfide and Polysulfide Donors on Insulin Sensitivity of the Adipose Tissue

Hydrogen sulfide (H(2)S) and inorganic polysulfides are important signaling molecules; however, little is known about their role in adipose tissue. We examined the effect of H(2)S 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 H(2)S and the polysulfide donors, Na(2)S and Na(2)S(4), respectively. In addition, the effect of Na(2)S and Na(2)S(4) on insulin-induced glucose uptake and inhibition of lipolysis was studied in adipose tissue explants ex vivo. Na(2)S and Na(2)S(4) administered in vivo at a single dose of 100 μmol/kg had no effect on plasma glucose and insulin concentrations. In addition, Na(2)S and Na(2)S(4) did not modify the effect of insulin on plasma glucose, fatty acids, and glycerol concentrations. Na(2)S and Na(2)S(4)had 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. Na(2)S(4), but not Na(2)S, 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.