CLINICAL CASES
451
[50.3]
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.”
[50.4]
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
degradation.
Cushing syndrome occurs from hypercortisolism over a long period
of time.
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.
REFERENCES
Boron WF, Boulpaep EL. Medical Physiology: A Cellular and Molecular Approach.
Philadelphia, PA: Elsevier Science, 2003; 1319.
Lin B, Morris DW, Chou JY. Hepatocyte nuclear factor lalpha is an accessory fac-
tor required for activation of glucose-6-phosphatase gene transcription by glu-
cocorticoids. DNA Cell Biol 1998;17:967-4.
Mahmoud-Ahmed AS, Suh JH. Radiation therapy for Cushing’s disease: a review.
Pituitary 2002;5:175-80.
Muller OA, von Werder K. Ectopic production of ACTH and corticotropin-releasing
hormone (CRH). J Steroid Biochem Mol Biol 1992;43:403-8.
Petersen DD, Magnuson MA, Granner DK. Location and characterization of two
widely separated glucocorticoid response elements in the phosphoenolpyruvate
carboxykinase gene. Mol Cell Biol 1988;8:96-104.
Phillips PJ, Weightman W. Skin and Cushing syndrome. Aust Fam Physician
2007;36:545-7.
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