Cortisol is synthesized in the of the adrenal cortex.
Cortisol is a steroid hormone that helps regulate the metabolic and immune pathways of our body.
Each gland is made up of an inner medulla, which secretes catecholamines, and an outer cortex.
The adrenal cortex itself is divided into three zones, each one secreting a different steroid hormone.
The outermost zone is the zona glomerulosa, which secretes mineralocorticoids.
And finally, there’s the zona reticularis that secretes androgens.
Cortisol production is controlled by the hypothalamus-pituitary axis.
The hypothalamus, which is at the base of the brain, secretes corticotropin releasing hormone which is sensed by the anterior, or front part of the pituitary gland.
In the anterior pituitary, the corticotropin releasing hormone binds to a surface protein on a group of pituitary cells, called corticotroph cells, and stimulates them to release adrenocorticotropic hormone, or ACTH, into the bloodstream.
Cortisol is structurally derived from cholesterol, which is a lipid molecule, and can slip in and out of cells relatively easily. As a result, cortisol isn’t stored - it gets secreted as it’s being produced.
Normally, cortisol secretion is pulsatile throughout the day, peaking in the morning around 6am. But cortisol is also secreted in response to various stressful stimuli - including hypoglycemia or low blood sugar, infections, caffeine, sleep deprivation, and psychological stress - like getting in a fight with your best friend.
With regard to the immune response, cortisol promotes an overall anti inflammatory state, by inhibiting the two main products of inflammation - prostaglandins and leukotrienes - as well as inhibiting interleukin-2 production by white blood cells.