Intracellular Ca²⁺ and Mg²⁺ Regulation for Insulin-Stimulated Glucose Uptake into Mouse Diaphragm Muscles

Abstract

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 μM 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.