UC Davis

Whereas adrenergic stimulation promotes cardiac function that demands more fuel and energy, how this receptor controls cardiac glucose metabolism is not defined. This study shows that the cardiac β₂ adrenoreceptor (β₂AR) is required to increase glucose transporter 4 (GLUT4)-mediated glucose uptake in myocytes and glucose oxidation in working hearts via activating the cardiac β₂AR and promotes the G inhibitory-phosphoinositide 3-kinase-protein kinase B cascade to increase phosphorylation of TBC1D4 (aka AS160), a Rab guanosine triphosphatase-activating protein, which is a key enzyme to mobilize GLUT4. Furthermore, deleting G-protein receptor kinase phosphorylation sites of β₂AR blocked adrenergic stimulation of GLUT4-mediated glucose uptake in myocytes and hearts. This study defines a molecular pathway that controls cardiac GLUT4-mediated glucose uptake and metabolism under adrenergic stimulation.