Vitamin D and Vitamin D Functions

Vitamin D

Formation of the active form of vitamin D:

• Calcitriol also called 1,25-dihydroxycholecalciferol is the active form of vitamin D
• Its synthesis requires Cytochrome, NADPH & molecular oxygen

vitamin D Deficiency:

• Vitamin D deficiency causes rickets in children & Osteomalacia in adults
• Features of it are as under:

vitamin D Daily requirements:

• The daily requirement of vitamin D is 400 IU

Functions Of Vitamin D

Enumerate the functions of vitamin D. Explain its importance in calcium metabolism 
Answer:

Functions of vitamin D:

• Calcitriol (1,25-dihydroxycholecalciferol) is the active form of vitamin D
• Its functions are as follows:
  1. Increases intestinal absorption of calcium & phosphate
  2. Essential for bone formation
  3. Minimizes excretion of calcium & phosphate

Importance in calcium metabolism:

In the intestine, Calcitriol binds with a systolic receptor & forms a Calcitriol-receptor complex.
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This enters the nucleus & interacts with DNA
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This induces the synthesis of calcium-binding protein
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This increases calcium absorption by the intestine
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This increases calcium level

• It also promotes calcification & remodeling of bone
• It increases the mobilization of calcium & phosphate from bone