VITAMIN- A
M.Prasad Naidu
MSc Medical Biochemistry, Ph.D,.
VITAMIN- A
 Structure
6C beta-ionine ring with 11C polyprenoid side chain with
alternate double bonds.
 Provitamin–beta ...
CH 3
CH 3H 3C
CH 3
CH 2OH
CH 3
VITAMIN A (RETINOL)
RDA: 0.7 mg
Poly isoprenoid side chain
VITAMIN A
 Retinol Retinal retinoicacid All-trans Retinal
common in circulation.
 11cis- Retinal form is present in rhod...
VITAMIN A
 Sources
Animal –marine fish liver oils
Plant - mangopapayacarrot
 RDA – 1000 ug  day
1 RE = 1ug of retinol = ...
VITAMIN A
.
FUNTIONS
1. Retinal and Retinol vision
2. Retinoic acid –
cell differentiation
glycoprotein synthesis
reproduction.
3.Be...
WALDS VISUAL CYCLE
 The Cyclic events that occur in the process
of vision is visual cycle. .
 Rhodopsin is a photorecept...
FUNCTIONS OF VIT A
WALDS
VISUAL CYCLE
DEFECIENCY
primary causes [dietary]
secondarycauses[malabsorption]
Results in
Night blindness
Conjunctival xerosis
Bitots ...
.
 Toxicity of vit-A is either due to
1. over-dosage of vit-A supplements
2. excess dietary intake [
 As vitamin A is no...
.
 Vit-A can be used to treat diseases where
epithelial surface is damaged.
 Retinoic acid acts on cell differentiation ...
VISUAL CYCLE
meta-rhodopsin
Transducin Transducin [A]
PDE PDE [A]
CGMP GMP
VISUAL CYCLE
Decreased CGMP
closes Na+ channels in rod cell membrane
hyper polarization of rod cell membrane
generation of...
VITAMIN D
 Structure
plants - Ergosterol Ergocalciferol [D2]
Active form in animals is calcitriol
UV
VITAMIN D
 Sources
1. sunlight
2. animal sources; fish liver oils  eggs
3. plant sources
4. food fortification ; milk but...
VITAMIN D
 Digestion  absorption  transport
Digested and absorbed in small intestine
using bile salts .
Vit-D is transpor...
VITAMIN D
 Synthesis of vit-D
 Regulation of synthesis by Ca and PO4.
 Low calcium stimulates PTH secretion which
activ...
FUNCTIONS
Vit-D plays a major role in regulation of calcium
and phosphate levels by mainly acting on 3
different organs.
...
VITAMIN D
 Deficiency
Children ---Rickets
Adults ------ Osteomalacia
VITAMIN D
 Toxicity
hyper-vitaminosis D causes toxic effects
like de-mineralization , hyper-calcemia ,
renal calculi etc.
ABSORPTION AND TRANSPORT
IRON DEFICIENCY ANEMIA
 Laboratory findings
 Hypochromic microcytic
anemia
 ferritin ( 30 to 300
Nanogm/ml)
 serum iro...
Dental fluorosis
THANK Q
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Vitamins

  1. 1. VITAMIN- A M.Prasad Naidu MSc Medical Biochemistry, Ph.D,.
  2. 2. VITAMIN- A  Structure 6C beta-ionine ring with 11C polyprenoid side chain with alternate double bonds.  Provitamin–beta carotene [Retinal+Retinal]  Active forms 1.Retinol 2.Retinal 3.Retinoic acid
  3. 3. CH 3 CH 3H 3C CH 3 CH 2OH CH 3 VITAMIN A (RETINOL) RDA: 0.7 mg Poly isoprenoid side chain
  4. 4. VITAMIN A  Retinol Retinal retinoicacid All-trans Retinal common in circulation.  11cis- Retinal form is present in rhodopsin.  Active forms are heat stable and light sensitive.
  5. 5. VITAMIN A  Sources Animal –marine fish liver oils Plant - mangopapayacarrot  RDA – 1000 ug day 1 RE = 1ug of retinol = 0.6 ug of betacarotene
  6. 6. VITAMIN A
  7. 7. . FUNTIONS 1. Retinal and Retinol vision 2. Retinoic acid – cell differentiation glycoprotein synthesis reproduction. 3.Beta-carotene- Anti-oxidant
  8. 8. WALDS VISUAL CYCLE  The Cyclic events that occur in the process of vision is visual cycle. .  Rhodopsin is a photoreceptor present in retinal rod cells.  Rhodopsin is a conjugated protein with 11-cis retinal and protein opsin.
  9. 9. FUNCTIONS OF VIT A WALDS VISUAL CYCLE
  10. 10. DEFECIENCY primary causes [dietary] secondarycauses[malabsorption] Results in Night blindness Conjunctival xerosis Bitots spots Corneal xerosis keratomalasia Blindness
  11. 11. .  Toxicity of vit-A is either due to 1. over-dosage of vit-A supplements 2. excess dietary intake [  As vitamin A is not excreted from the body it isccumulated in liver producing toxic effects  Toxicity produces headache , nausea , vomitings , liver damage alterations in the skin and mucous membranes etc.
  12. 12. .  Vit-A can be used to treat diseases where epithelial surface is damaged.  Retinoic acid acts on cell differentiation and growth therefore used as a drug.  It is used to treat diseases like Measles, Acne, Psoriasis , Leukemia etc.
  13. 13. VISUAL CYCLE meta-rhodopsin Transducin Transducin [A] PDE PDE [A] CGMP GMP
  14. 14. VISUAL CYCLE Decreased CGMP closes Na+ channels in rod cell membrane hyper polarization of rod cell membrane generation of nerve impulse to visual cortex
  15. 15. VITAMIN D  Structure plants - Ergosterol Ergocalciferol [D2] Active form in animals is calcitriol UV
  16. 16. VITAMIN D  Sources 1. sunlight 2. animal sources; fish liver oils eggs 3. plant sources 4. food fortification ; milk butter  RDA 200-400 IU day
  17. 17. VITAMIN D  Digestion absorption transport Digested and absorbed in small intestine using bile salts . Vit-D is transported from intestine to circulation by chylomicrons and stored in the liver.
  18. 18. VITAMIN D  Synthesis of vit-D  Regulation of synthesis by Ca and PO4.  Low calcium stimulates PTH secretion which activates 1- hydroxylase
  19. 19. FUNCTIONS Vit-D plays a major role in regulation of calcium and phosphate levels by mainly acting on 3 different organs.  Intestine ; increases absorption of Ca and PO4  Bone ; increases deposition of CaPO4 thus increasing mineralization of bones .  Kidneys ; reabsorbs Ca and decreases Ca excretion.
  20. 20. VITAMIN D  Deficiency Children ---Rickets Adults ------ Osteomalacia
  21. 21. VITAMIN D  Toxicity hyper-vitaminosis D causes toxic effects like de-mineralization , hyper-calcemia , renal calculi etc.
  22. 22. ABSORPTION AND TRANSPORT
  23. 23. IRON DEFICIENCY ANEMIA  Laboratory findings  Hypochromic microcytic anemia  ferritin ( 30 to 300 Nanogm/ml)  serum iron (50 to175 µgm/dl)  TIBC (300 to 350 µgm/dl)  transferrin (200 to 400 mg/dl) Spoon-shaped nails (koilonychia)
  24. 24. Dental fluorosis
  25. 25. THANK Q
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