Fig. 2

Activation of Keap1 and Nrf2 and their regulation in osteoblasts and osteoclasts. Oxidative Stress caused by aging and/or estrogen deficiency inhibits Keap1 and releases Nrf2 which subsequently migrates into the nucleus and activates antioxidant genes. Antioxidant proteins and GSH synthetase, which have positive effects on osteoblasts, negatively affect osteoclasts directly as well as indirectly via osteoblasts