Cortisol
Physiology · Biochemistry · Medicine
Say it: KOR-tih-sol
Cortisol is a steroid hormone made by the adrenal cortex that helps the body cope with stress, raises blood glucose and dampens inflammation.
Also: hydrocortisone
Definition
What is cortisol?
Cortisol is the main glucocorticoid hormone in humans, a steroid made from cholesterol in the middle zone of the adrenal cortex, the outer layer of the adrenal glands that sit on top of the kidneys. Its release is controlled by the hypothalamic-pituitary-adrenal (HPA) axis: the hypothalamus releases corticotropin-releasing hormone, which prompts the pituitary gland to release ACTH, which in turn stimulates the adrenal cortex. Rising cortisol then slows this chain by negative feedback. Levels follow a daily rhythm, normally highest in the morning and much lower later in the day.
Cortisol is often called the stress hormone because it drives the body's longer-term response to stress. It raises blood glucose by promoting the breakdown of glycogen, stored fat and muscle protein and the making of new glucose, keeping fuel available for the brain and muscles. It also helps maintain blood pressure and suppresses inflammation and immune responses, which is why synthetic glucocorticoid drugs are used for inflammatory conditions such as asthma.
Lasting excess cortisol, from tumors or long-term steroid medicines, causes Cushing syndrome, with weight gain, a rounded face and high blood glucose. Too little, as when the adrenal glands are damaged in Addison disease, causes weakness, weight loss, and low blood glucose and sodium.
Word parts
Where does the word “cortisol” come from?
- cort-
- bark, outer layer (here the adrenal cortex)Latin cortex
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Terms that go with it
- HormoneA hormone is a chemical messenger released into the blood by a gland or cell that changes the activity of distant target cells with matching receptors.
- Endocrine systemThe endocrine system is the set of glands and cells that release hormones into the blood to regulate growth, metabolism, reproduction and more.
- CholesterolCholesterol is a waxy steroid lipid found in animal cell membranes and used to make steroid hormones, vitamin D and the bile salts that digest fat.
- InflammationInflammation is the body's protective response to infection or injury, in which leaky, widened blood vessels bring immune cells and fluid to the site.
- Circadian rhythmA circadian rhythm is a roughly 24-hour cycle in an organism's body and behavior, driven by an internal clock and reset each day mainly by light.
- HomeostasisHomeostasis is the body's ability to keep internal conditions, such as temperature, blood glucose and pH, steady while conditions around it change.
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