The counterregulatory action of catecholamines on insulin- stimulated glucose transport and its relation to glucose transporter phosphorylation have been studied in isolated rat adipose cells. The results suggest that the phosphorylation state of the glucose transporter does not appear to be involved in either signaling transporter translocation or triggering changes in transporter intrinsic activity. Insulin shifts the steady state subcellular distribution of IGF-II receptors from a large intracellular pool to the plasma membrane in the rat adipose cell. In the present study, the counterregulatory effects of adrenergic stimulation, adenosine deaminase (ADA), and cAMP on this process have been studied. The results suggest that beta-adrenergic stimulation, through a cAMP-dependent mechanism, markedly alters the insulin-stimulated redistribution of IGF-II receptors. This effect is additional to the potent antagonistic action of cAMP on insulin's signaling mechanism.
