Kokras et al. (2018) showed that female Wistar rats (3 months old) enter the center of an open field test (OFT), indicative of lower anxiety levels, more often than males, but this affect was eliminated by ovariectomy or Letrozole treatment (intraperitoneal injection of 1 mg/kg letrozole for 8 days) indicating that systemic E2, and not central aromatase activity, may be responsible for the primary anxiolytic effect observed in females (Kokras et al., 2018). Here, CYP19A1 is linked to Anxiety.