A second rat received a shock whenever the first did, but was without control. The latter had far more glucocortiocid release. Many studies have examined whether the physiology of the stress- response differs among animals of different ranks. In stable hierarchies, dominant males have the lowest amounts of basal glucocorticoid secretion. They have the most control and numerous outlets for frustration.
Personality seems to play a major role in how dominant males respond to stress.
When stress causes an organism to secrete glucocorticoids repeatedly, the regulation of the system stops working as well, and the organism starts to hypersecrete glucocorticoids even under nonstressful circumstances. These rats have smaller stress-responses and return to baseline faster after the end of stress. Handling after 3 weeks of age does not cause the effect. Sex differences in glucocorticoid levels women tend to have higher glucocorticoid levels than mean. This was used for may years to suggest that women reacted more poorly to stress than men.