Regulation of Mg2+ homeostasis by insulin in perfused rat livers and isolated hepatocytes

Abstract

Several recent studies demonstrate that adrenergic receptor stimulation evokes marked changes in Mg²⁺ homeostasis. As insulin counter-regulates many of the metabolic consequences of adrenergic receptor stimulation, we evaluated the potential influence of insulin on Mg²⁺ movements in response to adrenergic stimulation. The data demonstrate that insulin is able to block the Mg²⁺ efflux from perfused rat livers stimulated by isoproterenol or 8-Br-cAMP, but has little or no effect on epinephrine or phenylephrine induced Mg²⁺ efflux. Thus, evidence is provided demonstrating that there are redundant adrenergic pathways regulating Mg²⁺ 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.