Ethnic differences in allopregnanolone concentrations in women during rest and following mental stress

The neuroactive steroid allopregnanolone (ALLO) is stress sensitive, negatively modulates the HPA axis, and has been implicated in mood disorders. We examined ethnic differences in plasma ALLO at rest and following mental stress in African American (AA) men (n = 21) and women (n = 24) and non-Hispanic White men (n = 24) and women (n = 25). Overall, AA women had lower ALLO concentrations than non-Hispanic White women (p <.05), especially following mental stress (p <.01). Only 20% of AA women showed the expected stress-induced increase in ALLO compared with 59% of non-Hispanic White women (p <.01). No ethnic differences were seen in men. For both ethnic groups, poststress ALLO was negatively correlated with poststress cortisol (p <.05). Results are interpreted to reflect dysregulation in ALLO mechanisms in AA women and may have implications for ethnic differences in mood disorders.