iThei mdcdaelcinfd o c elllllrllll ThofthThseThe Adrenals
The adrenal glands are almond-sized organs that sit on top of each kidney.
Each gland has two separate zones. The inner zone, or medulla, secretes
the hormones epinephrine (Epi, also known as adrenaline); norepineph-
rine (NE); and a small amount of dopamine in response to immediate
stress signaled by the central nervous system.
The outer zone of the adrenal gland is known as the cortex. The cortex se-
cretes three types of hormones: glucocorticoids, mineralocorticoids, and
androgens. These hormones are made from cholesterol and are essential
to everyday life in varied amounts throughout the day.
Glucocorticoids
The main glucocorticoid, cortisol is stimulated by the release of adreno-
corticotropin hormone (ACTH) from the pituitary gland. The primary
functions of cortisol are to help regulate blood sugar levels, increase body
fat, defend the body against infections, and help the body adapt to stress.
Cortisol also helps the body convert food into energy and has anti-in-
flammatory properties.
Mineralocorticoids
Aldosterone is the main mineralocorticoid. It helps regulate blood vol-
ume, blood pressure, and the body’s sodium and potassium levels.
Androgens
Dehydroepiandrosterone (DHEA) and testosterone are androgen hor-
mones present in both men and women. Women produce DHEA and
testosterone in both the adrenals and ovaries.
DHEA has been touted as the “youth” hormone; its production peaks
around age twenty and decreases over time. By age forty, our bodies make
about half the amount of DHEA as they did in our twenties; by age sixty-
five, 10–20 percent; and by age eighty, that drops to less than 5 percent
of the amount produced at age twenty. DHEA increases production of
insulin-like growth factor-1 (IGF-1), which is a signal for human growth
hormone, a powerful anti-aging hormone. DHEA enhances the body’s
ability to fight off infections, and higher levels have been associated with
reduced self-antigens. DHEA protects the body from the effects of corti-
sol and the stress that triggers its production.
The adrenal glands are responsible for manufacturing hormones from