Artem has a doctor of veterinary medicine degree.
Drinking & Urinating
Imagine just for a second that you are always extremely thirsty and passing large amounts of urine throughout the day. How much urine? About 5 times more than normal. Yikes!
What could possibly be the problem? Well, it may be that you have something called central diabetes insipidus, a condition caused by a lack of antidiuretic hormone as a result of something like a brain tumor. That's just the very basic gist of it, of course.
This lesson isn't about central diabetes insipidus though. It is, however, about antidiuretic hormone.
What Is Vasopressin?
The definition of central diabetes insipidus includes a special term: antidiuretic hormone (ADH), another name for vasopressin. Vasopressin is a very normal part of your body. It's a hormone that's produced by a structure in your brain called the hypothalamus. While it's produced in the hypothalamus, it's actually stored and released by another structure in the brain. After it's produced in the hypothalamus, vasopressin latches onto a protein and is carried to the pituitary gland. This gland, also a part of your brain, is the one that stores and secretes this hormone as necessary into your bloodstream.
Therapeutic Response to Vasopressin
So what therapeutic effect is vasopressin supposed to have and what does it all have to do with central diabetes insipidus? To understand this, let's get something basic out of the way first. The term antidiuretic hormone is actually quite descriptive of vasopressin's major therapeutic effect.
A diuretic, like the famous Lasix, is the more proper term for the lay term 'water-pill'. This means that a diuretic causes increased urine production. Logically, an anti-diuretic (like ADH), is then the exact opposite of this! It helps to preserve water within the body.
But if a person lacks enough naturally produced ADH, as per central diabetes insipidus, there's little to stop excess urine production by the body. Since the person is urinating out precious water en masse, they are also drinking like crazy to stay alive!
So if a patient has central diabetes insipidus and you were to give him/her vasopressin, then what would be the expected therapeutic response? Decreased urine production and thus decreased urinary output.
Why? The exact biochemical way vasopressin brings about this change is beyond this lesson's scope but we can simplify it to this. Vasopressin is administered to the patient. It then attaches to receptors, appropriately called vasopressin 2 receptors, located in the kidneys. Once it attaches to these receptors, it triggers a sequence of steps that enhance the reabsorption of water from the kidney's internal structures and back into the blood. Meaning, the person doesn't urinate out as much water and thus the body doesn't trigger an excessive feeling of thirst either.
In other words, you can imagine that the kidney is filled with internal piping made of semi-permeable material. Normally, water will be filtered from the bloodstream and into this internal piping by the kidney. From here, the water will go into the bladder. Vasopressin signals the kidney's internal pipes to reabsorb the water back into the bloodstream instead of pushing it through into the bladder. That's the essence of it.
In sum, decreased urine output is the appropriate therapeutic response to vasopressin.
Vasopressin is another name for antidiuretic hormone (ADH). This hormone is made by your hypothalamus but is stored and secreted by the pituitary gland. Deficiency of ADH may result in central diabetes insipidus, a condition caused by a lack of antidiuretic hormone as a result of something like a brain tumor. This will lead to excessive thirst and urination.
ADH preserves body water, and its lack thus excretes too much body water, resulting in lots of urination and thirst. Vasopressin is given therapeutically to tell the kidneys to reabsorb any water filtered from the bloodstream back into the bloodstream. This means vasopressin decreases urine output.
To unlock this lesson you must be a Study.com Member.
Create your account
Register to view this lesson
Unlock Your Education
See for yourself why 30 million people use Study.com
Become a Study.com member and start learning now.Become a Member
Already a member? Log InBack
Resources created by teachers for teachers
I would definitely recommend Study.com to my colleagues. It’s like a teacher waved a magic wand and did the work for me. I feel like it’s a lifeline.