Cortisol

Information

Identifying severe stress is an important basis for treating and preventing many diseases. The quantification of biological stress markers presents an efficient way to evaluate the effects of stressors, independent of their underlying cause. Here we talk about cortisol which is perhaps the most popular stress marker besides catecholamines.

Cortisol is produced in the cortex of the adrenal gland. Its production is induced by adrenocorticotropic hormone (ACTH) from the anterior pituitary, whose release is stimulated by corticotropin releasing hormone form the hypothalamus. The released cortisol then suppresses the release of ACTH through negative feedback. This entire series of regulatory influences is called the hypothalmic-pituitary axis.

Cortisol synthesis and release follows a circadian rhythm. It is highest during the first hour after one wakes up in the morning and the least during the early hours of night sleep. Once released into the blood, it is mainly bound to proteins. Only free cortisol (that is not bound to any proteins) is capable of diffusing into the saliva. This cortisol is biologically active and saliva makes a good medium for the determination of this biologically active form.