B. While the exact mechanism is not known, excess cortisol over long
periods of time mobilizes lipids and redirects fat deposition away
from the peripheral regions to the truncal region creating a “buffalo
hump” appearance between the shoulders and a “moon face.”
D. While all of the choices can lead to hypercortisolism, about two-
thirds of all cases are due to a pituitary adenoma that secretes excess
ACTH, leading to excess cortisol in the blood.
B IO C H E M IS T R Y PE A R L S
All steroid hormones are synthesized from cholesterol, with the rate-
limiting step in steroid biosynthesis being the cleavage of the
cholesterol side chain.
Cortisol is catabolic and carries out lipolysis and muscle tissue
Cushing syndrome occurs from hypercortisolism over a long period
Cortisol has numerous effects on the body, and in excess, can cause
hypertension, lipolysis, “buffalo hump,” “moon faces,” easy bruising
of the skin, and truncal obesity.
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