Insulin-like growth factor binding protein-2 expression is decreased by lithium.

Lithium has been shown to possess cytoprotective properties in both cellular and animal models. Moreover, previous studies indicate that lithium treatment alters the expression of insulin-like growth factor binding protein-1 (IGFBP-1), a critical modulator of insulin-like growth factor bioactivity. Given the critical roles played by insulin-like growth factors in cellular mitogenesis, differentiation, and cell death, and that IGFBP-2 is the major brain resident IGFBP, we assessed IGFBP-2 expression in primary cortical neuroncultures subsequent to lithium treatment. We report that 7 days of lithium treatment at therapeutically relevant doses attenuates the expression of IGFBP-2 mRNA and protein in a dose and time-dependent manner. Therefore, these results suggest a possible role for the insulin-like growth factor system in lithium's mechanism of action.