Calcirtriole
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Calcirtriole Presentation Transcript

  • 1.
  • 2. Calcitriol
    Muhammad Shahzeb
    Roll # 177
  • 3. Layout:
    Introduction
    Biosynthesis and regulation
    Transport
    Mechanism of action
    Metabolism
    Metabolic Actions
    Abnormalities associated with calcitriol
    - Hypovitamenosis D
    - Hypervitamenosis D
  • 4. Introduction:
    Calcitriol also called 1,25-dihydroxycholecalciferol,
    active form of vitamin D with three alcohol groups
    It increases the level of calcium (Ca2+) in the blood
  • 5. Biosynthesis and its regulation:
    Produced in the cells of the proximal tubule of the nephron
    By the action of 25-hydroxyvitamin D3 1-alpha-hydroxylase
    The activity of the enzyme is stimulated by
    - PTH.
    - Prolactin
    - Decreased levels of serum phosphate
  • 6. skin
    7-dehydro cholesterol
    Previtamin D3
    Vitamin D3
    25-hydroxylase
    liver
    25-hydroxycholcalciferol
    25 hydroxycolcalciferol 1-hydroxylase
    kidney
    1,25-dihydroxycol calciferol
  • 7.
  • 8. Transport:
    Vitamin D-binding protein belongs to the albumin family
    458 amino acids
    Coded by 1690 nucleotides on chromosome 4
    Found in
    -plasma,
    -cerebrospinal fluid
    -on the surface of many cell types
    It binds to vitamin D and its plasma metabolites and transports them to target tissues
  • 9. Mechanism of action:
  • 10. Metabolism:
    Half life - approx. 5-8 hours.
    This enzyme plays a role in calcium homeostasis and of calcitriol
    24-hydroxylase
    calcitriol
    Calcitric
    acid
  • 11. Metabolic Actions
  • 12.
  • 13. Intestinal Ca+2 absorption:
    Increases the absorption of Ca
    Increases the production of Calmodulin (CaBP).
  • 14. On bones:
    Type 1 Collagen
    osteoclastin
    Osteoblasts Osteoclast
    absorption of Cain bones
  • 15.
  • 16. Action on kidneys
    A major action of calcitriol is to regulate renal 25-hydroxyvitamin D,-1-hydroxylase
    It has been shown that calcitriol brings about a suppression of this enzyme
    Thus it helps to regulate the formation of calcitriol by negative feedback inhibition.
  • 17. On skeletal and cardiac muscles
    the rate of Ca uptake by sarcoplasmic reticulum of skeletal muscles
    skeletal muscle mass
    Can cause the calcification of cardiac muscle
    Lead to myocardial failure
  • 18. On cancer cells:
    Cancerous cells have receptors for calcitriol
    Calcitriol represses the cell proliferation
    So it along with its analogs can be use for treating the cancer
  • 19. On skin:
    melanin synthesis.
    preventing the skin penetration of sunlight.
    7-dehydrocholesterol is not converted to pre-vitamin D
    Feedback regulation.
  • 20. Endocrine functions:
    Parathyroid Gland:
    Inhibits the proliferation of parathyroid cells
    Inhibits the parathyroid genes form transcription
    Thus can be used to treat hyper-parathyroidism.
    Pituitary gland
    Increases prolactin synthesis and secretion from pituitary cells.
  • 21. Pancreas:
    vitamin D deficiency inhibited insulin secretion from the pancreas, whereas vitamin D repletion improved insulin secretion
  • 22. Disorders related to calcitriol:
    Vitamin D deficiency:
    Type I:
    Type II:
    Body is unable to utilize vitamin D due to defect in the receptor of calcitriol.
    hydroxylase
    25,OH –D3
    calcitriol
  • 23. Diseases related to vitamin D deficiency
    Rickets
    - Softening of bones in children potentially leading to fractures and deformity in bones
    • The predominant cause is a vitamin Ddeficiency
    Sign & symptoms:
    Bone pain or tenderness
    dental problems
    muscle weakness
    Growth disturbance
    Hypocalcemia
    Tetany
  • 24. Treatment and prevention:
    Increase dietary intake of calcium, phosphates and vitamin D.
    Exposure to sunlight
    cod liver oil
  • 25. Osteomalacia
    Osteomalacia is the softening of the bones due to defective bone mineralization
    Signs and Symptoms
    Weak bones
    Bone pain
    Muscle weakness
    Hypocalcemia
    Compressed vertebrae
    Fractures
    Bone softening
    Bending of bones
    Pain
  • 26. Treatment
    Oral administration of vitamin D.
    Osteomalaciadue to malabsorption may require treatment by injection of significant amounts of vitamin D.
  • 27. Hypervitaminosis D
    Is tolerable
    But deleterious in extreme large dosage 500-1000 times than normal
    Effects:
    Immediate effects:
    Anorexia
    Thirst
    Lassitude(fatigue)
    Constipation
    Polyuria
    Nausea
    Vomiting
    Diarrhoea
  • 28. Delayed effects: persistent hypercalcemia and hyperphospatemia may result
    Urinary lithasis
    Metastatic calcification
    Effecting
    • Kidneys
    • 29. Bronchi
    • 30. Arteries
    • 31. Muscles
  • review
  • 32.
  • 33. References
    Research paper by U Sipmson & Ronald
    www.wikipedia.com
  • 34. Acknowlegdements
    Allah Almighty
    Parents
    Prof. Dr. Khawaja Muhammad Fayyaz
    Dr. ShafqatNazir
    Dr. JamshedIqbal.
    Mam Jawaria
    Mam Uummaya
  • 35. Friends
    HaroonGull
    UsmanBaig.
    Musa Khan
    Ali Aasil
    Talha Tariq
    Mudassir Butt
    MaazBarlas
    AtifRana
    AbubakrDastgir
    AtharSaleem
    GulamMurtaza Sahib
  • 36. Thanks to all of
    U!