Can magnesium act as a second messenger? Current data on translocation induced by various biologically active substances

Free intracellular Mg2+ ([Mg2+](i)) can potentially integrate the signals f rom hormones, cellular metabolism and organismal ion homeostasis and affect the activities of ion channel and other effecters. Interest in [Mg2+](i) h as been heightened by recent reports that small changes in [Mg2+](i) in the physiological range can significantly modulate Important cellular function s. In addition, a variety of new evidence shows that [Mg2+](i) instantaneou sly changes following stimulation with various biologically active substanc es. These observations suggest that [Mg2+](i) may act as a second messenger .