stress hormone
a chemical that is part of the body’s response to threats and other stressors. The primary stress hormone is cortisol. Others include epinephrine, norepinephrine, and corticotropin. Together they put the body into a state of alertness (see fight-or-flight response), accompanied by increased heart rate and respiration, dilated pupils, sweating, diminished sensitivity to pain, and redirection of blood from the gastrointestinal tract to muscles. Long-term exposure to stress hormones, as in ongoing child abuse or living in a war zone, is one of the causes of posttraumatic stress disorder and has been implicated in the etiology of depression and cancer.