Cushing syndrome is a cluster of clinical features resulting from exposure to excess glucocorticoids (hypercortisolism). Most of the abnormalities in Cushing syndrome are caused by high levels of cortisol itself, but an accompanying excess of androgens and mineralocorticoids like aldosterone may also add to the syndrome. Cortisol is produced continuously in the adrenal gland. It even has a specific circadian pattern. This means it is at its highest peak in the morning after we wake up from sleep and gradually declines during the day. The lowest concentration is typically in the late evening, before bedtime, with a big decrease around midnight. Levels also vary based on the day’s activities.

Cortisol is part of the fight-or-flight response that helps us react to unexpected and frightening circumstances. Produced in the adrenal gland’s zona fasciculata, cortisol does three main things:

Increases blood pressure

Changes metabolic activity

Decreases the inflammatory response

Cortisol increases blood pressure by upregulating α1 adrenergic receptors in the arterioles. This increases their sensitivity to norepinephrine and epinephrine, leading to vasoconstriction. Cortisol also increases insulin resistance and facilitates gluconeogenesis, lipolysis, and proteolysis; these changes help the body prepare to battle stressors—or run from them. Furthermore, cortisol modulates the immune response and decreases the body’s inflammatory and immune reactions by a variety of mechanisms.

From this perspective, cortisol seems to help us battle external threats, which means its presence in the human body is welcome. However, prolonged secretion and chronic high levels of cortisol causes hypercortisolism (Cushing syndrome), leading to other effects:

Decreased fibroblast activity and poor wound healing

Decreased osteoblast activity and therefore slower bone formation

Reduced immune response and therefore increased infections

Chronic increased serum glucose, leading to a secondary form of diabetes

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from our Musculoskeletal, Skin, and Connective Tissue collection, which is available for free.

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You will get 5 days of full access to our Rx360+ program, including nearly 800 Rx Bricks.  After the 5-day period, you will still be able to access over 150 free bricks, including the entire collections for General Microbiology and Cellular and Molecular Biology.