Ca++ Metaboloism-BDS
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Transcript of Ca++ Metaboloism-BDS
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Calcium:Functions
Excitation
contraction-in musclesExcitation secretion -inglands
Release oftransmittersfrom nerve
ending.
Intracellular
messengers forhormones,autacoids &
transmitters.Impulsegeneration in
heart-automaticity, A-V conduction.
Coagulation ofblood.
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Ca++ stores, HomeostasisHealthyadult menand
women 1300 and1000 g ofcalcium9% is in boned teeth
Normalserumcalcium
concentration8.5 to 10.4
mg/dl
Ionized (50%),protein-bound(40%),and complexed
(10%).
The extracellularCa2+ concentrationtightly controlled byhormones.Entry at the intestineand\its exit at the
kidney;These samehormones regulate
withdrawal from thelar e
8.5 to 10.4mg/dl
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Hormonal control of plasma concentration
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RemodellingBone[Ca++] turn
over:
Constant andcontinuous
Osteoclastic activity
followed byosteoblastic-Remodelling
Remodelling deficits
accumulate over lifetome
Diet, Ex., hormones,drugs etc
Remodelling
Remodelling
ResorptionNew bone formationClosely coupledDirectionally opposite
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Excretion
Absorption
Facilitated diffusion-All intestine
Carrier-DuodenumInfluenced by D
Phytate, oxalate,phosphate, TC
chelate Ca++
Phenytoin &Glucocorticoids
Excretion
Ionized Ca++ isfiltered
Reabsorbed
Influenced by
HormonesThiazide excretion
Ca++ requirement
300mg/d is lost
Same amount hasto be
supplememted
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Preparations and usesOral
Calcium chloride,lactate, carbonateetc.
Parenteral
Ca gluconate-i.v.Produces warmth oninjection
Uses
Ca gluconate slowi.v. followed byinfusion
Dietary
supplement ingrowing children,pregnancy andlactating mothers.
As adjuants inosteoporosis
Antacids
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hormone[PTH][Parathormone]
Actions:
Increases plasmaCa++Boneresorption.[Followedby new boneformation]
Kidney:Increases
reabsorptionIntestine: Indirectlyby increasing theformation of Calcitrol
Uses
Not used inhypoparathyroidism-Expensive,Parenteral route of
delivery, Vit D canproducecomparable resuts.
Teriparatide-
RecombinantSometimes used inosteoporosis
Diagnostic; Pseudo
and true
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CalcitoninCalcitonin
Calcitonin is aHYPOCALCEMIChormone actions-oppose those of PTH.
Secreted by thyroidparafollicular C cells
Preperations
Porcine
Synthetic
Route
S.C, i.m., Nasal spray.
Uses
Calcitonin useful inmanaginghypercalcemia[Malignancy]
Pagets disease toreduce bone pain
Osteoporosis
Not routinely used
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Alfacalcidol[1 OHD 3
Prohormone
Converted inbodyto active
hormone[Calcitriol]
Vit D
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Cutaneous
[Under
UV]
Dietary[Animal D3-
Dairy, Fish,egg yolk][Plant-D2]
Liver[25Hydroxylation]
25-OHVitD
Kidney[1
Hydroxylation]Kidney[1 -25(OH)2VitD]
Calcitriol Vitamin D synthesi
and activation
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Vit: D: Actions
[1]
synthesis of Ca++ binding proteins
[2]
[2] bone resorption
[3]
] Increases tubular reabsorption
Result= Plasmaconcentration
Of Ca++
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Vit D: Actions
synthesis of Ca++ binding proteins
bone resorption
Increases tubular reabsorption
Other actions
On Immunological cells On Lymphikine production
Neuronal, skeletal muscle function
Plasma
concn.Of Ca++
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Vit D DefeciencyNutrional
def.
Ca++Plasmaconcn
PTHsecretion
Ca++MobilizedFrom bones
Bonemineralization
Rickets[Children
]
Osteomalacia
[Adults]
Hypervitaminosis??PK??
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Preparations Uses
1g of
cholecalciferol=40i.uCalciferol
Cholecalciferol
Calcitriol
Alfacalidol-
Does not requirerenal hydroxylation
Can be used in renalimpairment
Calcipotriol[Analogue]
psoriasis
Prophylaxis-Dose??
D Resistant rickets[Hereditary]
DDependent[hereditary]
Calcitriol/alfacalcidol
Renal rickets
Calcitriol/alfacalcidol
Osteoporosis
Hypoparathyroidis
m
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OsteoporosisCharacterized by decreased bone strength
Common among postmenopausal women
Defective organic matrix
Pathological factors
Multifactorial-Etiology
ManagementLifestyle
HRT, SERM,BISPHOSPHONATES, Ca++, VitD
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BisphosphonatesCLASSIFICATIONI Generation 1-
10
EtidronateII Generation 100-
1000
Palmidrnate,Alendronate
III generation 1000-5000
Risedronate,Zoledronate
ACTIONS
Prevent osteoporosisPrevent bone
USES
Ostoporosis
Pagets disease
Hypercalcemia ofmalignancy
Bone pain inmetastasis
ADEGastric irritantsSevere esophagitisTo be swaalowed
with a glass of
water in sitting