Effects of strontium on calcium-dependent hexose transport in muscle.

Hexose transport in isolated perifused rat and guinea pig left atria and in isolated intact rat hemidiaphragms was followed by measuring the tissue/medium distribution of the nonmetabolized glucose analog, 3-O-methyl-D-glucose. Stimulation of 3-methylglucose transport by insulin, hyperosmolar medium, K+-free medium, and ouabain was depressed or absent in Ca2+-free medium. Addition of 2 mM Sr2+ to Ca2+-free media restored the response of transport to the stimulatory factors. Sr2+ also increased basal hexose transport. The Ca2+ dependence and the effect of Sr2 was greatest in guinea pig atria and least in rat hemidiaphragms. It is concluded that Sr2+ plays a Ca2+-like role in the regulation of hexose transport.