INS and type 2 diabetes mellitus: This conclusion is based on the following results: i) Acute exposure to low extracellular Mg2+ has no effect on insulin secretion from either isolated mouse islets of Langerhans or INS-1 cells; ii) In islets cultured at 25 mM glucose, to mimic the hyperglycemic state found in T2DM, insulin secretion was actually enhanced by reducing extracellular Mg2+; iii) The mRNA expression levels of Mg2+ channels/transporters and key players in GSIS, in both islets and INS1 cells, were unaffected by extracellular Mg2+.