Furthermore, in vitro studies have shown that the chloroform extract (CE-C) of deer antler appears to inhibit osteoclast differentiation by suppressing the activation of extracellular signal-regulated kinase (ERK), protein kinase B (PKB/Akt), the inhibitor of kappa B (I-κB), which would be increased by RANKL under osteoporosis conditions (Li et al., 2007). This evidence concerns the gene AKT1 and osteoporosis.