Normalization of insulin sensitivity with lithium in diabetic rats.

Lithium salts are commonly used in psychiatric patients and have been shown to have an insulinlike action in vitro. To define the impact of lithium ion on in vivo glucose metabolism, the effect of 2 wk of lithium treatment on plasma glucose and insulin concentrations, insulin-mediated glucose disposal, and skeletal muscle glycogen synthesis in normal and diabetic rats was examined. Our results demonstrated the ability of lithium ions to completely restore insulin sensitivity to normal in diabetic rats. The insulin-mimetic activity of the cation seems to be highly specific for the glycogenic pathway in skeletal muscle. These results raise the possibility that lithium ion may prove effective in reversing the defect in glycogen storage that characterizes non-insulin-dependent diabetes mellitus in humans.