Concentration and metabolism of serotonin in selected brain areas during pregnancy and lactation in the rat.

Serotonin (5-HT) and its major metabolite, 5-hydroxyindole acetic acid (5-HIAA), were assayed in hypothalamus, hippocampus, and cortex during selected stages of pregnancy and lactation in the rat. No changes in 5-HT were observed in any of the brain areas analyzed. However, concentrations of 5-HIAA in hypothalamus and hippocampus, though not in cortex, showed marked changes during the immediate postpartum period. The significance of these changes is discussed in terms of possible hormone-neurotransmitter relationships.