Role of Hydrogen Sulfide and Polysulfides in the Regulation of Lipolysis in the Adipose Tissue: Possible Implications for the Pathogenesis of Metabolic Syndrome

Hydrogen sulfide (H(2)S) and inorganic polysulfides are important signaling molecules; however, little is known about their role in the adipose tissue. We examined the effect of H(2)S and polysulfides on adipose tissue lipolysis. H(2)S and polysulfide production by mesenteric adipose tissue explants in rats was measured. The effect of Na(2)S and Na(2)S(4), the H(2)S and polysulfide donors, respectively, on lipolysis markers, plasma non-esterified fatty acids (NEFA) and glycerol, was examined. Na(2)S but not Na(2)S(4) increased plasma NEFA and glycerol in a time- and dose-dependent manner. Na(2)S increased cyclic AMP but not cyclic GMP concentration in the adipose tissue. The effect of Na(2)S on NEFA and glycerol was abolished by the specific inhibitor of protein kinase A, KT5720. The effect of Na(2)S on lipolysis was not abolished by propranolol, suggesting no involvement of β-adrenergic receptors. In addition, Na(2)S had no effect on phosphodiesterase activity in the adipose tissue. Obesity induced by feeding rats a highly palatable diet for 1 month was associated with increased plasma NEFA and glycerol concentrations, as well as greater H(2)S production in the adipose tissue. In conclusion, H(2)S stimulates lipolysis and may contribute to the enhanced lipolysis associated with obesity.