“…For example, binding estrogen to ER-α ( Choleris et al, 2003 , 2012 ), progesterone ( Schumacher et al, 1990 ), interleukin-6 ( Terzidou et al, 2006 ), H 2 S ( Wang et al, 2019 ), and carotenoid ( Avraham et al, 2019 , 2021 ) induce OXTR expression. Among them, we were particularly interested in the estrogen system because the endogenous estrogen deficiency might desensitize predator odor exposure-induced short-term changes in cognitive behaviors and long-lasting changes in social behaviors ( Gao et al, 2021 ). In addition, the orexin system plays a regulatory role in social or fear behavior ( Faesel et al, 2021 ).…”