Progesterone Promotes Anti-Anxiety/Depressant-like Behavior and Trophic Actions of BDNF in the Hippocampus of Female Nuclear Progesterone Receptor, but Not 5α-Reductase, Knockout Mice.

Progestogens' anti-anxiety and anti-depressive effects and mechanisms are not well-understood. Progestogens are hypothesized to have anti-anxiety and anti-depressive effects on behavior, independent of actions at nuclear progestin receptors (NPRs) and dependent on allopregnanolone (5α-pregnan-3α-ol-20-one; 3α,5α-THP), a 5α-reduced, neuroactive metabolite of progesterone (P). Adult c57 mice in behavioral estrus (proestrus; pro) showed more anti-anxiety-like and anti-depressant-like behavior and higher levels of estradiol (E), P, and allopregnanolone in the hippocampus/amygdala complex.