Lead researcher Mark Wilson of the Yerkes National Primate Research Center and Emory University in Atlanta found corticotropin releasing factor is a key neurohormone involved in stress response. "Corticotropin releasing factor is located in several different brain regions, serving different functions," Wilson said in a statement. "Its release is important for our ability to adapt to every day stressors and to maintain our physical and emotional health."

In response to stress, corticotropin releasing factor levels rise; corticotropin releasing factor levels decrease when the stressor no longer is present. Chronic stress, however, increases the length and volume of expression of corticotropin releasing factor in areas of the brain associated with fear and emotion, including the amygdala -- the brain.

"In our study, rats that continuously were exposed to corticotropin releasing factor from this area of the brain experienced anxious and depressive behavior, decreased libido and disrupted ovarian cycles suggesting that persistent release of CRF such as occurs in chronic stress clearly affects multiple body systems," says Wilson. "These behavioral changes are similar to what we see in human females who are exposed to stressors on a daily basis."

The findings are reported in the online edition of Molecular Psychiatry.