Glucocorticoids, a type of hormone in rats, affect how they respond to cocaine. When the rats had their glucocorticoids suppressed, they moved less when given cocaine. Adding back different levels of glucocorticoids reversed this effect. Removing the adrenal glands or blocking glucocorticoid receptors also reduced the response to cocaine. The level of glucocorticoids at the time of adrenal gland removal influenced the long-term response to cocaine. Overall, glucocorticoids play a role in how rats react to drugs like cocaine.