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HORMONES THATHORMONES THAT

REGULATE CALCIUMREGULATE CALCIUM

METABOLISMMETABOLISM• PARATHYROID ( PTH )

• CALSITRIOL

•CALSITONIN

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DEVIATION OF CALCIUM REGULATION : LIVE THREATENING

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1 KG CALCIUM IN OUR BODY, 9 ! IN BONE

1! OF BONE CALCIUM IS FREELY EXCHANGEABLE "ITH

EXTRACELLULAR FLUID CALCIUM

PLASMA CALCIUM :

  COMPLEX "ITH ORGANIC ACID

PROTEIN BOUND (ALBUMIN # GLOBULIN)

  IONIZED FORM : IMPORTANT FOR BIOLOGIC ACTIVITY  1$1 % 1$& ''*L

  CONC$ CHANGE : MUSCLE PARALYSIS

  COMA

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HYPOALBUMIN : DECREASE CALCIUM PLASMA

 ACIDOSIS : INDREASE IONIZED FORM CALCIUM

 ALKALOSIS : ENHANCE BINDING TO ALBUMIN

  DECREASE IONIZED FORM

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PTH (PARATHYROID HORMONE)

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PREPROPARATHYROID HORMONE

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PTH ACTION

G PROT

 AC

PTH

REC

CAMP

KINASE

BIOLOGIC RESPONS

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PTH AFFECTS CALCIUM HOMEOSTASIS

1$ INCREASE DISSOLUTION OF BONE

+$ REDUCE RENAL EXCRETION OF CALCIUM

&$ INCREASE CALCITRIOL IN INTESTINE C ABSORPTION

-$ INCREASE RENAL EXCRETION OF PHOSPHATE

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PATHOPHYSIOLOGY

TYROID SURGERY, AUTOIMMUNE DISEASE HYPOPARATHYROIDISM

  SERUM : CALCIUM PHOSPHATE

 

MUSCLE CRAMP

TETANY

LARINGOSPASM

DEATH

CATARACT

PSEUDOHYPOPARATHYROIDIMS (INHERITED)

NORMAL PTH, DEFECT IN G PROT OR DO"NSTREAM CAMP SIGN$

  SHORT STATURE,

SHORT METACARPAL METATARSAL

  MENTAL RETARDATION

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SECONDARY HYPERPARATHYROIDISM

  RENAL FAILURE

DECREASE PRODUCE OF CALCITRIOL

IN RENAL PARENCHYMA

CALCIUM ABSORBPTION IN GUT

 

PTH

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CALCITRIOL

DIET

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CALCITRIOL ACTION

CALCITRIOL EFFECT :

  INCREASE ABSORPTION OF CALCIUM AND PHOSPHATE

THROUGH NUCLEAR RECEPTOR

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PATHOFPHYSIOLOGY

RICKETS

LO" PLASMA CALCIUM AND PHOSPHATE

  SKELETAL DEFORMITY

  INHERITED AD : DEFECT IN CONVERSION +.OH/D& TO CALCITRIOL

  AR : DEFECT IN CALCITRIOL NUCLEAR RECEPTOR

VIT D DEFICIENCY IN ADULT OSTEOMALACIA

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CALCITONIN

  &+ AMINO ACID

  PRODUCED BY PARAFOLLICULAR CELL OF TYHROID

ROLE IN CALCIUM HOMEOSTASIS : UNCLEAR