Regulation of glycogen metabolism in hepatocytes through adenosine receptors. Role of Ca2+ and cAMP.

The objective of this work is to identify the adenosine receptor subtype and the triggered events involved in the regulation of hepatic glycogen metabolism. Glycogenolysis, gluconeogenesis, cAMP, and cytosolic Ca2+ ([Ca2+](cyt)) were measured in isolated hepatocytes challenged with adenosine A1, A2A, and A3 receptor-selective agonists. Stimulation of adenosine receptor subtypes with selective agonists in Ca2+ media produced a dose-dependent increase in [Ca2+]cyt with A1>A2=A3, cAMP with A2A, glycogenolysis with A1>A2A>A3, and gluconeogenesis with A2A>A1>A3, in addition, a decrease in cAMP was observed with A1=A3.