Serum and glucocorticoid-regulated protein kinase were discovered by Webster et al. in 1993 when they studied rat breast cancer cells through differential screening of glucocorticoid-induced transcriptional expression. The SGK gene is named serum and glucocorticoid-regulated protein kinase (SGK) because of its rapid 5-10 fold increase in SGK expression within 30 minutes when stimulated by glucocorticoid or serum. Three isomers of mammal SGK have been found, namely SGK1, SGK2 and SGK3. The structural homology of the three isomerases is up to 80%, but the chromosome location, tissue distribution, function and regulation of the three isomerases are different. In addition to glucocorticoid, serum and halocorticoid induction, SGK can also be induced and activated by osmotic pressure, uv, ischemia, trauma and other stress factors, and plays an important role in the regulation of ion channels, cell proliferation, survival and apoptosis signal transduction.