The effects of lithium and of magnesium ions on adenosine 3',5'-monophosphate (cyclic AMP) accumulation in isolated rat hemidiaphragms were investigated. Magnesium ions caused a small but significant increase in the basal concentration of cyclic AMP, whereas lithium ions had no effect. However, pretreatment of tissues with LiCl caused a significant dose-dependent reduction in the effect of epinephrine on the concentration of cyclic AMP. Magnesium ions enhanced the rise in tissue cyclic AMP caused by epinephrine, but this stimulatory effect of magnesium ions was reduced in tissues that had been pretreated with LiCl. It was concluded that lithium ions act at an intracellular site to inhibit hormone-induced accumulation of the cyclic nucleotide and was proposed that magnesium and lithium ions act at different cellular locations to produce their effects on hormone-induced cyclic AMP accumulation.
ASJC Scopus subject areas