Ovarian steroid hormones. Effects on mood, behaviour and brain excitability.

Estradiol and progesterone both accumulate in the brain. Specific cytosol receptors are present in certain CNS regions. Estradiol increases but progesterone decreases the brain's excitability. The effects can be mediated via monoamine systems or a change in monoamine metabolizing enzymes, but other mechanisms are possible. The combination of estradiol and progesterone seem to provoke a negative mood change in certain sensitive women. Estradiol and progesterone singly seem not to have these negative effects on mood, but perhaps positive effects instead.