Intracellular Ca2+ and Mg2+ regulation for insulin-stimulated glucose uptake into mouse diaphragm muscles.

We investigated whether the changed levels of intracellular Ca2+ and Mg2+ in mouse skeletal muscles affected insulin-stimulated glucose uptake. Insulin alone had no effect on 45Ca2+ efflux and uptake. A23187 at 20 microM increased 45Ca2+ influx and inhibited insulin-stimulated 14C-glucose uptake with normal external concentrations of Ca2+ and Mg2+ or in the absence of both cations. These results suggest that the increase in Ca2+ influx into, and in Mg2+ efflux from, skeletal muscles may inhibit insulin-stimulated glucose uptake.