Regulation of Mg 2+ homeostasis by insulin in perfused rat livers and isolated hepatocytes

Several recent studies demonstrate that adrenergic receptor stimulation evokes marked changes in Mg 2+ homeostasis. As insulin counter‐regulates many of the metabolic consequences of adrenergic receptor stimulation, we evaluated the potential influence of insulin on Mg 2+ movements in response to adrenergic stimulation. The data demonstrate that insulin is able to block the Mg 2+ efflux from perfused rat livers stimulated by isoproterenol or 8‐Br‐cAMP, but has little or no effect on epinephrine or phenylephrine induced Mg 2+ efflux. Thus, evidence is provided demonstrating that there are redundant adrenergic pathways regulating Mg 2+ efflux from liver tissue. One of these pathways, the β‐adrenergic component, is selectively blocked by insulin. Furthermore, these findings may provide a cellular explanation for hypomagnesemia associated with diabetes.