Cortisol is manufactured from cholesterol by the adrenal glands. Its secretion is controlled by hormones released from the pituitary gland and hypothalamus . Cortisol levels vary according to a daily (circadian) rhythm , but peak at times of stress. It stimulates the central nervous system , increases water retention and blood sugar levels (available energy), stimulates the metabolism of proteins (to repair injuries), and regulates blood pressure. Cortisol is also an anti-inflammatory and anti-allergic agent, and reduces the actions of the immune system . Molecules from the same family, such as cortisone, are used as medications to control inflammation, allergy (asthma), and graft rejection.






