Which Comes First?

Periodically, a blog will actually be the response to a reader’s question. I’ve received several questions lately. The first thing I do when I receive a question is to be sure the reader understands that I am not a doctor and that no matter what I research for them, they must clear the information with their nephrologist before taking any action. Today’s question was asked by a long time reader who already understands my terms for researching for her.

That’s a pretty big build up for a common sense question. But, at least now you understand how I handle reader questions and may want to ask one (or more) of your own.

Back to the question at hand: What is the connection between PTH and creatinine and which causes a problem with the other?

What’s PTH, you ask. Let’s find out. You and your Hormones: an educational source from the Society of Endocrinology at https://www.yourhormones.info/hormones/parathyroid-hormone/ was a great deal of help here:

“Alternative names for parathyroid hormone

PTH; parathormone; parathyrin

What is parathyroid hormone?

The parathyroid glands are located in the neck, just behind the butterfly-shaped thyroid gland.

Parathyroid hormone is secreted from four parathyroid glands, which are small glands in the neck, located behind the thyroid gland. Parathyroid hormone regulates calcium levels in the blood, largely by increasing the levels when they are too low. It does this through its actions on the kidneys, bones and intestine:

  1. Bones – parathyroid hormone stimulates the release of calcium from large calcium stores in the bones into the bloodstream. This increases bone destruction and decreases the formation of new bone.
  2. Kidneys – parathyroid hormone reduces loss of calcium in urine. Parathyroid hormone also stimulates the production of active vitamin D in the kidneys.
  3. Intestine – parathyroid hormone indirectly increases calcium absorption from food in the intestine, via its effects on vitamin D metabolism

Got it? Okay then let’s remind ourselves what creatinine is. I wrote the following in last December 24th’s blog:

“A good place to start is always at the beginning. By this, I wonder if I mean the beginning of my Chronic Kidney Disease awareness advocacy as the author of What Is It and How Did I Get It? Early Stage Chronic Kidney Disease and the blog or if I mean the basics about creatinine. Let’s combine them all. The following definition is from the book which became the earliest blogs:

Creatinine clearance: Compares the creatinine level in your urine with that in your blood to provide information about your kidney function’

Hmmm, that didn’t exactly work. Let’s try again. Bingo! It was in SlowItDownCKD 2014,

Creatinine: chemical waste product that’s produced by our muscle metabolism and to a smaller extent by eating meat. {MayoClinic.org}”

That was nine years ago, but the information remains the same today.

So now, we know what both PTH and creatinine are, but what’s the connection? According to VIVO Pathophysiology, Colorado State University at http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/thyroid/pth.html :

Suppression of calcium loss in urine: In addition to stimulating fluxes of calcium into blood from bone and intestine, parathyroid hormone puts a brake on excretion of calcium in urine, thus conserving calcium in blood. This effect is mediated by stimulating tubular reabsorption of calcium. Another effect of parathyroid hormone on the kidney is to stimulate loss of phosphate ions in urine.”

To recap so far, we know what both PTH and creatinine are and what the connection between the two is. Now we need to know if one causes the other and, if so, which.

Chronic kidney failure. Your kidneys convert vitamin D into a form that your body can use. If your kidneys function poorly, usable vitamin D may decline and calcium levels drop. Chronic kidney failure is the most common cause of secondary hyperparathyroidism.”

Thank you to the Mayo Clinic at https://www.mayoclinic.org/diseases-conditions/hyperparathyroidism/symptoms-causes/syc-20356194 for this information.


Whoops! You may need a few reminders to understand the Mayo Clinic’s information, so here they are. Vitamin D helps the body absorb calcium properly. Calcium is necessary for strong bones and teeth. Many people don’t know it’s also necessary for blood clotting, nerves and heart. “Hyper” means over or, in this case, high as in above the necessary. Remember that when calcium or vitamin D is low, PTH rises. In my mind’s eye, I see a scale balancing the two out.

I did not find any information about PTH causing high creatinine. That doesn’t mean there isn’t any. It just means there isn’t any I could access. I found a journal site that looked promising, but it turned out to be for endocrinologists only. Too bad for us.

I do hope I’ve answered my reader’s question to her satisfaction. I know I enjoyed learning all this new information. You’re right: that’s my signal for a topic change.

“The Kidney Project is a national research initiative with a goal to create a small, surgically implanted, and free-standing bioartificial kidney to treat renal failure. RSN Founder and President Lori Hartwell catches up with Dr. Shuvo Roy who is a bioengineer professor at the University of California San Francisco to learn what is next for the Kidney Project and when clinical trials might begin. Dr. Shuvo Roy is passionate about this device that will mimic the kidneys and take the place of dialysis. Listen in to this exciting and hopeful show.

Listen in to the first conversation about the Kidney Project with Dr. Shuvo Roy.

 Learn more about the Kidney Project and Dr. Shuvo Roy

It’s an exciting time in the world of Chronic Kidney Disease Awareness right now. Even the government has acknowledged it’s time to deal with CKD patients. Keep on the lookout for more and more updates.

Until next week,

Keep living your life!