Vitamin D has two main forms, D2 and D3. It is a steroid compound that plays an essential role in regulating calcium and phosphorus metabolism. The active form, calcitriol, maintains normal plasma calcium and phosphorus levels by acting on the intestine, bone, and kidneys. A vitamin D deficiency can lead to rickets in children, characterized by soft bones and skeletal deformities.

2. Other names of Vitamin D
Cholecalciferol
Calciferol
Antirachitic factor
Sun-shine Vitamin

5. Vitamin D is a steroid compound.
There are two forms of vitamin D
7-Dehydro
cholesterol
Cholecalciferol
(Vitamin D3)
Ergosterol Ergocalciferol
(Vitamin D2)

6. Vitamin D is a steroid compound.

9. RDA for Vitamin D is…
200 – 400
IU 5 – 10 μg
1μg of vitamin D = 40 IU

10. Dietary vitamin D is
absorbed in the duodenum
along with lipids.
It is transported to the liver
through chylomicron.

12. Active form of vitamin D is…
1, 25-dihdroxy
cholecalciferol
(1,25 DHCC)
Or also called
Calcitriol

13. It plays an essential role as a hormone in the
regulation of calcium & phosphorus metabolism.

14. It maintains the normal plasma level of calcium
and phosphorus by acting on…
Intestine bone Kidneys

15. Action of calcitriol on intestine
Intestine
•plasma calcium & phosphorus
conc.
• Synthesis of calcium binding
proteins calbindins.
•absorption of calcium &
phosphorus from the intestine

16. Action of calcitriol on bone
Bone
• It is believed that calcitriol has both anabolic
& catabolic role on bone.
• It promotes the mineralization of bones
(anabolic)
• D3 along with PTH stimulates the
mobilization of calcium & phosphorus from
bone (catabolic)

17. Action of calcitriol on kidneys
Kidneys
• The reabsorption of calcium
& phosphorus from the kidney
• Excretion of calcium &
phosphorus.

18. Plasma
Calcium
PTH
1,25DHCC
Ca mobilization from
bone
Renal reabsor-ption of
Cacium
Renal excretion of
Cacium
Plasma
Calcium
Ca absorption from
intestine

22. Decreased serum calcium
Soft & pliable bones
Bone deformities
Delayed dentition
Delayed closure of anterior fontanelle

23. bow legs 
 Knock knee

24. rickety rosary 
 pigeon chest

25. bossing of
frontal bones 
Delayed closure of
anterior fontanelle

27. Decreased serum calcium
Insufficient mineralization
Soft & pliable bones
Increased osteoporosis
Bone deformities

29. Renal Rickets
•In chronic renal failure synthesis of calcitriol
in kidney is impaired
•As a result, the deficiency of calcitriol occurs
which leads to hypocalcemia &
hyperphosphatemia
•It can be treated by oral or intravenous
administration of calcitriol

30. Vitamin D Resistant Rickets
•Involve a defect in the metabolism or
mechanism of action of calcitriol.
•defective vitamin D receptor
•defective 1, α-hydroxylase activity in
kidney
•liver disease and kidney failure (
production of 25-HCC & 1,25 DHCC
respectively)

31. •High intake over the period of time.
•Early symptoms -
•Nausea, vomiting, anorexia, increased
thirst, loss of weight, etc
•Hypercalcemia
•Metastatic calcification