Expression of adenosine receptors in cardiac fibroblasts as a function of insulin and glucose level

Adenosine among other factors is known to regulate the growth and function of cardiac fibroblasts (CFs). Its action is mediated by cell-surface receptors linked to a variety of signaling systems. The goal of present work was to examine the effects of glucose and insulin on adenosine receptors (ARs) mRNA and protein level in primary culture of rat CFs by means of real-time PCR and Western blot. Elevated glucose level increased the expression of A1-AR, A2A-AR, decreased the expression of A3-AR, and had no effect on A2B-AR expression. On the other hand insulin suppressed the expression of A1-AR, and A2B-AR, and had no effect on A2A-AR and A3-AR expression. Our measurements showed that accumulation of cAMP in response to ARs agonists correlated well with the changes in receptors expression level. These results indicate that changes in glucose and insulin level independently and differentially regulate the ARs expression and functional state in CFs.