Stimulatory effect of paeoniflorin on adenosine A-1 receptors to increase the translocation of protein kinase C (PKC) and glucose transporter (GLUT 4) in isolated rat white adipocytes.

In an attempt to understand the subcellular signals after activation of adenosine A-1 receptors, paeoniflorin was employed to incubate with rat white adipocytes in vitro. Translocation of protein kinase C (PKC) beta-subtype from cytosol to membrane was enhanced by an incubation with paeoniflorin in a concentration-dependent manner similar to that of porcine insulin. Also, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) inhibited this action of paeoniflorin in a concentration-related fashion and it markedly attenuated the action of paeoniflorin at a concentrations sufficient to block the action of adenosine. Moreover, chelerythrine inhibited the paeoniflorin-stimulated translocation of PKC in a way similar to that stimulated by porcine insulin. Subcellular inhibition is considered because stimulation of porcine insulin was not modified by DPCPX at concentrations sufficient to block adenosine A-1 receptors. Similar results were also observed in adipocytes regarding the translocation of glucose transporter (GLUT4) from cytosol to membrane. Thus, we found that paeoniflorin can activate adenosine A-1 receptors to increase the translocations of PKC and GLUT4, two major signals for glucose uptake, from cytosol to membrane of the white adipocytes in rats.