PRL and Anxiety: Prolactin induces the activation of MPOA neural circuitry,34,35 the rewarding stimulus to dams,36 restraint of aggressive behavior,37 and prevention of anxiety-like behavior.38 These indispensable roles of prolactin in cultivating maternal behavior partly explain why the only placental Sod3 KO-induced decreased expression of prolactin showed the comprehensive feature of poor maternal behavior.