ASK DR. BAUGHAN                                                         April 14, 2000

CORTISOL CLOCKS

A reader asked, “Please write about am and pm cortisols.”

Our bodies have many built-in clocks.  One of them is in the adrenal glands.  The adrenal glands sit like little caps on top of the kidneys.  They produce a variety of important hormones, including cortisol.  Cortisol is the body’s natural version of cortisone.  It plays a major role in modulating how we respond and cope with stresses, be they emotional, physical (including infections or trauma) or relatively incidental (such as getting up in the morning).  Like so many ways the body tries to teach us, balance is the key to normal, healthy cortisol production.  The adrenal clock produces more cortisol around 8 am and 4 pm.

We must keep this in mind if we need to test the adrenals for under or over production.  Low production of cortisol is called Addison’s Disease, or adrenal insufficiency.  For much of the day, though, we produce very little cortisol.  So if we tested any old time and the result was low, we would not know if it was normally low for that time of day or whether it was always low.  But if it is low at 8 am, then the possibility of Addison’s Disease is greater.  The symptoms of Addison’s Disease include weakness, weight loss, low blood pressure and blood sugar, potassium abnormalities, and a gradual darkening of the skin in light-skinned people.  The production of cortisol is regulated by another hormone, ACTH, produced by the pituitary gland behind the eyes.  If the cortisol is low, the next test to confirm Addison’s Disease is to give ACTH (brand name Cortrisyn) and see if the cortisol level goes up appropriately.  In Addison’s Disease, the adrenal cannot respond enough, and the level stays low.

The overproduction of cortisol is called Cushing’s Disease, and is usually caused by a tumor in the adrenal gland.  Sometimes a tumor elsewhere in the body will cause cortisol production, too.  Again, since the level naturally varies during the day, a time had to be picked to standardize the blood level.  In Cushing’s Disease, the level may be high all the time, so sometimes a random level is drawn.  Another approach is to test when cortisol should be at its highest (all together now . . .), yes, 8 am!  If the level is even higher than it should be, then Cushing’s Disease is suspect.  The symptoms of Cushing’s Disease include weight gain, elevated blood pressure and blood sugar, weakness, development of a rounded face and fat pad at the base of the neck, osteoporosis, glaucoma, cataracts, and vertical lines in the abdomen called striae.  To further investigate for Cushing’s Disease, we try to get the cortisol production to temporarily shut down.  In the Dexamethasone Suppression Test, a dose of a strong steriod medicine is given at midnight, then the cortisol level is checked at 8 am the next morning.  If it is still elevated, the next step is usually to do a CT scan of the abdomen to see if there is a small tumor on one or both adrenal glands.

The most common malfunction of the adrenal glands, though, is in reaction to certain medicines, referred to as “steroids,” though more fully as “corticosteroids.”  The most commonly used one is Prednisone.  Corticosteroids are different from “anabolic steroids,” which are the type athletes abuse to get bigger muscles.  Prednisone and its relatives can be invaluable in many diseases and are quite safe in younger people for shorter periods of days to a couple of weeks.  In high doses for long periods, they can cause the same problems as Cushing’s Disease.  So we try to use them for the shortest period possible or in the lowest dose that is effective.  While on high doses, the adrenal glands will not bother to produce cortisol.  If Prednisone is suddenly stopped, the adrenal glands may not promptly resume production.  This would then create a state of sudden adrenal insufficiency, or an “Addisonian crisis,” with very low blood pressure and extreme fatigue.  In older people, this may happen up to 6 months or even a year after being on Prednisone if they are stressed (such as having surgery or getting an infection), and their adrenal glands cannot respond by increasing cortisol production in response to stress.  Therefore, always inform your health providers if you are or have ever taken steroids such as prednisone, dexamethasone (Decadron), or prednisolone.  Being ready to give these medicines if they are needed can prevent the life-threatening crisis.