Trifluoperazine inhibition of insulin-induced increase in skeletal muscle glucose uptake

The ability of trifluoperazine, a calmodulin blocker, to prevent increases in skeletal muscle glucose uptake induced by insulin was tested. Insulin significantly increased glucose uptake by the rat hindlimb and trifluoperazine (10(-6) M) completely inhibited this increase. We conclude that calmodulin is a factor involved in the regulation of insulin-mediated glucose transport in muscle cells.