Basics of Adrenal Gland Hormone Production
The adrenal glands are endocrine glands, which mean they secrete stuff inside your body that can affect the functioning and/or the activity level of other organs. You may remember from school that the endocrine system also includes the hypothalamus, pituitary gland, thyroid gland, and reproductive organs, namely the ovaries and testes. Optimal functioning of the adrenal gland is important for the entire endocrine system to work well.
Your adrenal glands help regulate many important biological processes by producing hormones. A hormone is a substance, usually a protein that an organ produces to help regulate or control the function of another organ or body process. For example, the ovaries and the adrenal glands make estrogen, which regulates the menstrual cycle.
Aldosterone production by the adrenal glands
Aldosterone is a hormone produced by the adrenal cortex, specifically the zona glomerulosa. Aldosterone is important in regulating blood pressure and regulating salt and water in the body:
Regulating blood pressure: In treating high blood pressure, physicians and other healthcare providers look at the renin-angiotensin-aldosterone system (RAAS). Aldosterone production is closely linked to the kidneys, which make the hormones renin and angiotensin. Angiotensin directly stimulates the adrenal glands to produce aldosterone; aldosterone then regulates blood pressure by causing the kidneys to hold on to more sodium when the blood pressure is low.
In adrenal fatigue, the adrenal glands may not produce adequate amounts of aldosterone (in addition to not producing other hormones like cortisol). This is a major cause of the low blood pressure that can be seen in adrenal fatigue.
Regulating salt and water: If you consume too much sodium in your diet, the high sodium intake causes a decrease in the production of aldosterone by the adrenal glands, so your kidneys eliminate the excess sodium. If you're dehydrated or your blood pressure is low, your adrenal glands make more aldosterone to signal the kidneys to hold on to that sodium.
Helping the kidneys maintain acid-base balance: Aldosterone can stimulate the kidneys to eliminate the excess acid the body doesn't need. Adrenal fatigue can affect the kidneys’ ability to eliminate this excess acid.
Cortisol production by the adrenal glands
The adrenal glands (specifically, the zona fasciculata) produce the hormone cortisol. Cortisol has multiple functions, and every one of them is vital:
Cortisol is important for your immune health because it reduces inflammation (see the nearby sidebar).
Cortisol prevents your blood glucose levels from dropping too low (a condition called hypoglycemia).
Cortisol helps regulate blood pressure. The adrenal glands increase cortisol production when your blood pressure is low.
Sex hormone production by the adrenal glands
The adrenal glands (in particular, the zona reticularis) are responsible for producing sex hormones. Examples of these hormones are DHEA, pregnenolone, and androstenedione. The hormones are important in the production of testosterone in the testes and estradiol (think estrogen) in the ovaries, but they also affect other organs.
DHEA: DHEA, or dehydroepiandrosterone, helps maintain your immune system. It has a role in lowering inflammation. As you get older, your body produces less DHEA. The adrenal glands’ decrease in DHEA production can actually begin in your early thirties. In many chronic illnesses, the levels of DHEA can be very low.
Pregnenolone: Pregnenolone is called a precursor hormone because it's needed for the production of many other hormones, one of them being DHEA. Normally, pregnenolone blocks the effects of cortisol. Studies have shown that pregnenolone has beneficial effects on memory and nerve function. It also helps you get a good night's sleep.
Androstenedione: This hormone is closely linked to testosterone and estradiol:
Testosterone: Testosterone plays a key role in the development of male reproductive tissues such as the testes and prostate. It's responsible for secondary sexual characteristics such as increased muscle, increased bone mass, and the growth of body hair. Androstenedione (from the adrenal glands) is the common precursor of testosterone.
Testosterone is important for women as well. It helps women improve muscle strength as well as maintain healthy bone mass. It's also vital for maintaining a healthy libido in women.
Estradiol: The adrenal glands produce androstenedione, which is essential for producing estradiol. Estradiol, which is one of the three estrogens occurring in women, is the predominant estrogen during the reproductive years.
Epinephrine and norepinephrine production by the adrenal glands
Everybody has been really scared at one time or another. Think about a experiencing a near-miss in traffic, finding a rattlesnake on the hiking trail, or hearing your child scream in the front yard. Everything changes instantly.
You may have felt the adrenaline rush as an immediate flow of something from your middle back out to your arms and legs. At that point, your heart rate was rapid. Maybe you felt flushed, broke out in a sweat, or had palpitations. Your blood pressure probably increased. These body changes are due to the hormones epinephrine, also called adrenaline, and norepinephrine.
Epinephrine and norepinephrine are the two hormones produced in the inner aspect of the adrenal gland — the adrenal medulla. They're big contributors to your body's fight-or-flight response, and they affect the body's nervous system.