Vitamin D is one of the most important vitamins required by the human body for maintaining blood calcium levels which in turn is required for bone strength. it is produced by human skin when it is exposed to sunlight. Its levels decrease in patients suffering from end-stage renal or kidney diseases.

1. VITAMIN-D
BY : MISHA MANSOOR
ROLL NO. 171
BATCH-D

2. VITAMIN
‘’ Organic compound that is required in the diet in small
amounts for the maintenance of normal metabolic integrity.’’
LIPID-SOLUBLE
VITAMINS
WATER-SOLUBLE
VITAMINS
Vitamin-A Vitamin-B12
Vitamin-D Vitamin-B6
Vitamin-E Vitamin-C
Vitamin-K Niacin, Riboflavin, Thiamin

3. .

4. VITAMIN-D CHEMISTRY
Secosteroid
ACTIVE FORM : 1,25-dihydroxy cholecalciferol /
calcitriol
PROVITAMIN VITAMIN
7-Dehydrocholestrol Vitamin-D3
[ Cholecalciferol ]
Ergosterol Vitamin-D2
[ Ergocalciferol ]

5. RECOMMENDED DAILY
ALLOWANCE RDA
200 – 400 IU/day
5 – 10 microgram/day
Where,
1 microgram of Vitamin-D = 40 International
Unit

6. Major Source

7. DIETRY SOURCES

8. STRUCTURE

9. 7-dehydrocholestrol
Previtamin D
Cholecalciferol
UV
Thermal
isomerization
SYNTHESIS OF VITAMIN-D IN SKIN

10. ABSORPTION
• Absorption occurs in small intestine or duodenum
• Absorbed along with lipids
• Require bile salts
TRANSPORT
• Bonded to Vitamin-D Binding Globulin

11. METABOLISM OF VITAMIN-D
Cholecalciferol
[ vitamin D3 ]
Calcidiol
[25-hydroxy cholecalciferol ]
24,25-dihydroxy vitamin D
INACTIVE FORM
Calcitriol
[1,25-
dihydroxycholecalciferol]
ACTIVE FORM
25-hyroxylase
1-hydroxylase
24-
hydroxylase
Skin
Liver
Kidney

12. R
E
G
U
L
A
T
I
O
N .

13. FUNCTIONS
• Homeostasis
• Regulate cell maturation
• Synthesis and secretion of hormones
• Reduces Risk of obesity, insulin resistance and
metabolic syndromes such as cancer.

14. MECHANISM OF ACTION
1. Acts as Group-1 Hormones
2. Effects Calcium Transporters

15. CALCIUM HOMEOSTASIS
1. Increases intestinal absorption of calcium
2. Reduces excretion of calcium
3. Mobilizes bone minerals

16. EFFECT ON INTESTINE
Increase Ca Uptake into the intestinal
cell
Ca binds to cytosolic receptors
Ca- Receptor complex moves into
nucleus
Interacts with response elements
Enhance expression of Calcium
binding CALBINDIN

17. Parathyroid Hormone
Calcitriol
Ca mobilization from bones
Renal reabsorption of calcium
Renal excretion of calcium
Ca absorption from intestine
Serum
Calcium
Serum
Calcium
R
E
S
P
O
N
C
E
T
O
L
O
W
S
E
R
U
M
Ca

18. PATHOLOGIES
VITAMIN-D DEFICIENCY
Causes:
• Inadequate supply
• Impaired absorption
• Impaired production of 25-hydroxy VitaminD3
• Impaired production of 1,25 dihydroxy VitaminD3
• Resistant to effects of 1,25 dihydroxy VitaminD3

19. DISEASES RESULTING FROM VIT-D
DEFICIENCY
1. Rickets
2. Osteomalacia

20. Rachitic
rosary

21. VITAMIN-D TOXICITY
COMPLICATIONS
1.Calcinosis
2.Contraction of blood vessels leading to Inc. BP