NSC 23766, a cell-permeable compound, is a reversible and specific inhibitor of Rac GTPase. Its primary application lies in the field of cancer treatment.

NSC 23766 (100 μM) treatment effectively inhibits polar body emission in a dose-dependent manner. At 200 μM, it increases the percentage of morphologically abnormal spindles in oocytes. In NSC 23766-treated oocytes, p-MAPK protein expression is significantly decreased[2]. NSC23766 (50 μM) combined with 100 ng/mL Jagged1, GDF9, and BMP15 reduces germline cell cysts and increases primordial follicles[3]. Additionally, NSC23766 significantly inhibits GTP-Rac1 activity and the phosphorylation of Rac1-PAK, ERKs, and p38 MAPK in spinal dorsal horn neurons[4].

NSC23766, administered intraperitoneally at a dosage of 2.5 mg/kg/day, markedly delays the onset of spontaneous diabetes in NOD mice without notably influencing their growth, as measured by body weights. Furthermore, this compound significantly elevates the expression levels of Rac1 and CHOP, an endoplasmic reticulum (ER) stress marker, in the islets of NOD mice[1].