Last week we discussed the importance of the endocrine system and the problems associated with the too much and too little activity of the adrenal glands. This week, I thought we would stay with those glands, but look at an entirely different function of them. As you may recall, the two diseases associated with the adrenal glands highs and lows were Addison’s and Cushing’s. They are primarily due to increased or decreased levels of cortisol inside the body. However, the adrenal glands also play a huge role in regulating our blood pressure. It is possible that your antihypertensive medication regulates some component of the adrenal glands without even knowing it.
To begin, I always like to think of our circulatory system like a hydraulic bucket lift on a tractor. In order to get the bucket moving, several things must be in good working order. First, you need to have a fully function pump in order to keep pressure on the hydraulic lines. In this instance, our heart is the pump that circulates and provides pressure on the lines. Next, you need hydraulic lines that are intact and the proper fit. Our blood vessels provide this. Finally, my tractor needs the correct amount of hydraulic fluid inside those lines. That is, you guessed it, our blood.
Now, back to our body. If there is too little hydraulic fluid, I mean blood, inside of us, we won’t function properly. To combat this, our adrenal glands play an important role in keeping us balanced. This might seem complicated at first glance, but it truly is not. When the body detects that fluid levels have dropped, it will begin to secrete a chemical called renin. Renin is actively looking the chemical angiotensin and, after it is found, will work to break up the compound. This broken chemical is now called angiotensin I. After it circulates in the blood, it will eventually come to the lungs where it mixes with another chemical called angiotensin converting enzyme (Ace) to form angiotensin II. Angiotensin II is circulated back to the adrenal glands and is taken in to produce the hormone aldosterone. Aldosterone works to keep sodium inside the bloodstream. This is important because water follows salt and the more water we have in our blood, the thicker it will be and the higher our blood pressure will become. This entire process is called the renin-angiotensin-aldosterone system (RAAS).
This is a great self-defense process if you are low on blood pressure. However, many of the people in Mississippi have the exact opposite problem. If you suffer from high blood pressure, this system still happens and increases the blood pressure even more. This isn’t all bad though. Many of our blood pressure regulating medications work in some fashion of disrupting the RAAS. One large group works to stop the conversion of angiotensin I into angiotensin II. Angiotensin covering enzyme (ACE) is released by the lungs and is the final step before it goes to the adrenal glands to make aldosterone. A large class of high blood pressure medications are created through the stopping of this process. They are called ACE inhibitors. Common medications in the ACE inhibitor family includes Lotensin, Capoten, and Lisinopril (which I take daily).
Another class of antihypertensive that work with this principal are angiotensin II receptors which, as the name implies, block the receptor sites on the adrenal glands to prevent the formation of aldosterone. To a lesser extent, some medications work to reduce the amount of water that you have in your blood after the RAAS reflex happens. These are called diuretics and cause you to urinate more often, therefore reducing the total circulation volume of fluid and decreasing the workload on the heart. These are sometimes paired with an Ace inhibitor to decrease blood pressure. For example, the diuretic Hydrochlorothiazide (HCTZ) is usually paired with Lisinopril. Another common diuretic is Lasix, however, this is mainly used in the treatment of congestive heart failure with the goal of reducing the workload of the heart.
No matter how you slice it, our adrenal glands are critical to good life. Of course, there are ways that we can take charge of our blood pressure by reducing our sodium intake, quitting smoking, and getting excess weight under control. If you do take medications for your blood pressure that are aimed at changing a function of the adrenal gland, make sure you monitor yourself for skin rash, loss of taste, or a chronic cough. If you experience any of these symptoms, it might be time to adjust your medication. Stay safe out there.
M. Eric Williams, MS, NR-P is a syndicated columnist and the Assistant Director of Emergency Medical Technology Education at Jones County Junior College. He is a current Doctoral researcher at Delta State University and has 15 years’ experience in Emergency Medicine. If you have questions or comments, you may contact him at eric.williams@jcjc.edu
