The role of the sun in making vitamin D.
Vitamin D plays an important role in the absorption of calcium from the intestines and in maintaining the amount of calcium in the bones. However, vitamin D is not a function in itself, but it regains its original and functional state after such actions.
Cholecalciferol (vitamin D3) is formed in the skin
Cholesterol, also known as vitamin D3. This compound is formed in the skin. It is present in the skin due to the uv rays present in sunlight.
7-dehydrocholesterol
Comes into being from People who spend most of their time in the sun are not deficient in vitamin D. We also take vitamin D in our diet.
25-hydroxycholecalciferol of cholesterol
To be converted into liver
The first step in activating cholecalciprol is to convert cholecalciprol to 25-hydrocolciprol. This process takes place in the liver and is produced in limited quantities because 25-hydrocolcolprol has its own inhibitory feedback system that controls it. does .
This process regulates the concentration of 25-hydrocollocysterol in the blood plasma and on the other hand it also controls the conversion of vitamin D3 to 25-hydrocolocalciprol.
Formation of 1,25-dihydrocholecalciprol in the kidneys and control by parathyroid hormone
In the proximal tubules of the nephron in the kidneys, 25-hydrocalciceprol is converted to 1,25 diahydrocoliclesprol. These are the most active forms of vitamin D.
1,25 of 25-hydrocollocephalus. The presence of parathyroid hormone is essential for the conversion of dihydrocholecalciprol to 1.25 in the absence of these hormones. Dihydrocholecalciprol does not form.
Calcium ion concentration and 1,25. Formation of dihydrocholecalciprol
Calcium ions and 1,25. The opposite is true of dihydrocholecalciprol. When the amount of calcium ions is high, 1,25. There is a decrease in the formation of dihydrocholecalciprol and when the amount of calcium ions is high, the opposite happens, i.e., the amount of 1,25-dihydrocolcalciprol increases. There are two main reasons for this.
First of all, calcium ions, 25. Hydrocoliclesporol has a very small role in inhibiting the conversion of 1.5 to 25 hydrocolloids.
Second, when the amount of calcium ions in the body is high, it causes the production of parathyroid hormone in small amounts, which reduces the production of 1,25-dihydrocholecalciprol.
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