Short-term stimulation by adenosine of basal and insulin-induced glycogen synthesis in rat adipose tissue

The effects of adenosine on glycogen metabolism have been studied in isolated fat-pads from epididymal adipose tissue. Adenosine caused a sustained short-term increase in the incorporation of [U-14C]glucose into glycogen, as well as a stimulation of both basal and insulin-induced [1-14C]glucose oxidation. Adenosine produced changes also in the activity of glycogen synthase and phosphorylase, these effects being apparent only when glucose was present in the incubation medium. The addition of adenosine prevented the depressed synthesis of glycogen observed in the presence of dibutyryl cyclic AMP. In the presence of adenosine deaminase, the stimulation by insulin of glycogen synthesis was markedly decreased. The results suggest that adenosine may have a regulatory role on glycogen synthesis by facilitating the glucose transport.