Insulin lowers blood glucose by promoting the uptake of glucose from the bloodstream into adipose and muscle cells. If this function of insulin is impaired, diabetes develops. Treating diabetes therefore requires either supplementing insulin or enhancing insulin's glucose uptake effect.

Consequently, the global medical community is actively developing drugs that enhance insulin's glucose uptake effect. However, drug development has been limited because the mechanism by which insulin promotes intracellular glucose uptake has not been clarified.

The Jeonbuk National University (JBNU) research team has overcome this limitation and opened a path toward developing new diabetes treatments, drawing attention from the international academic community.

A research team composed of Professor Han Myung-kwan and Professor Kim Woo-hyun of the Medical School, Dr. Song Eun-kyung, and Dr. Kim Hyun-gak, among others, has, for the first time worldwide, demonstrated that insulin induces the production of NAADP, a molecule that raises intracellular calcium concentration, and thereby increases intracellular calcium to promote glucose uptake into cells.

These findings were published in the latest issue (November 22) of Cell Reports, the open-access journal of the leading life sciences journal Cell, and have generated significant attention in the international academic community.

The Han research team also, for the first time, showed that rosiglitazone, a diabetes drug previously used, increases NAADP production and thereby enhances glucose uptake into cells, accounting for its therapeutic effect.

For this study, Professor Han's team demonstrated that administering NAADP alone into cells produced a glucose uptake effect without administering insulin. This suggests the possibility of controlling blood glucose either by directly using NAADP or by using drugs that enhance the activity of the enzyme that synthesizes it.

Professor Han Myung-kwan stated, "This study will lay the foundation for a molecular and cellular biological understanding of how insulin mediates glucose uptake," and added, "Ultimately, it is expected to promote the development of drugs that enhance glucose uptake and contribute to diabetes treatment."