α1-Adrenergic stimulation causes Mg2+ release from perfused rat liver

The possibility that Mg2+ mobilization is stimulated in perfused liver by α1-adrenergic agonists was studied by measuring Mg2+ release in response to 0.5 and 20μM phenylephrine. During preperfusion exogenous Mg2+ was added to the medium to give 1.2 mM. 5 min before starting the addition of phenylephrine the infusion of exogenous Mg2+ was stopped. Mg2+ in the perfusate leaving the liver was measured by atomic absorption spectroscopy. Analysis of the Mg2+ decay curves with two exponential models indicated that phenylephrine caused dose-dependent Mg2+ release from perfused rat livers.