BIOKIMIA MINERAL - Biokimia... · PDF fileBIOKIMIA MINERAL Calsium Phosphor Iron Zinc...

Click here to load reader

  • date post

  • Category


  • view

  • download


Embed Size (px)

Transcript of BIOKIMIA MINERAL - Biokimia... · PDF fileBIOKIMIA MINERAL Calsium Phosphor Iron Zinc...







    Dr Nur Rahman, STP MP


    Jumlah mineral paling banyak dlm tubuh

    sekitar 1.5%-2% berat bb dan 39% of total

    minerals tubuh.

    99% calcium ada di bone and teeth

    1% of calcium is in the blood and extracellular

    fluids and within the cells of all tissues, yg

    berfungsi mengatur metabolisme.

  • Calcium occurrence

    In nature

    Tidak ada yg bebas

    Occurs mostly in soil systems as limestone (CaCO3), gypsum (CaSO4*2H2O) & fluorite (CaF2)

    In the body

    The most abundant mineral

    Average adult body contains app. 1 kg

    0,1 % in the extra cellular fluid

    1 % in the cells

    The rest (app. 99 %) in the skeleton (Bones can serve as large reservoirs, releasing calcium when

    extracellular fluid concentration decreases and storing excess calcium)

  • Calcium functions

    Elemen penyususn utama tulang dan

    gigi calcium phosphate

    (Ca10(PO4)6(OH)2 (hydroxyapatatite)

    Komponen struktur sel

    Kekuatan tulan tgt dari konsentrasi l


  • Hormone regulation of

    calcium-phosphorus metabolism

    Parathyroid hormone

    (PTH) Organ-target: bones, kidneys

    Function of PTH - increase of Ca

    concentration in plasma


    1. Releasing of by bones

    (activation of osteoclasts

    resumption of bones)

    2. Increase of reabsorbing in


    3. Activation of vit. D synthesis

    and increase of absorption

    in the intestine

    Vitamin D Thyreocalcitonin

    Organ-target - bones

    Function - decrease of Ca

    concentration in plasma

  • Pathways of Calsium

    Metabolism Pengaturan metabolism

    Calsium melibatkan :

    intestinal absorption (gut),

    blood calsium (Ca) and

    Phosphate (P) concentrations,


    the kidneys-which produce the

    hormonal form of vit D-and

    parathyroid glands (PTG),

    mengeluarkan parathyroid

    hormone (PTH).

    Rendah serum calsium or

    high serum phosphate level

    stimulates pengeluaran PTH n

    (Step 1) through negative


  • Calcium functions (Bone) Osteoclasts (bone cells)

    remodel the bone by

    dissolving or resorbing


    Osteoblasts (bone

    forming cells) synthesize

    new bone to replace the

    resorbed bone

    - Found on the outer

    surfaces of the bones

    and in the bone cavities

  • Calcium functions

    Berperan penting dlm pengaturan tbuh .

    A passive role: - As a cofactor beberapa enzymes (e.g. Lipase) and proteins

    - As component dlm pembekuan blood

    An active role: as an intracellular signal - In the relaxation and constriction of blood vessels

    - In cell aggregation and movement

    - In muscle protein degradation

    - In secretion of hormones as insulin

    - In cell division

    - In nerve impulse transmission

  • Calsium diabsorsi di semua bagian

    small intestine, paling cepat di bagian

    duodenum, dlm kondisi acidic medium

    (pH < 7) prevails

    Absorption, Transport, Storage,

    and Excretion

  • Calsium is absorbed by two mechanisms :

    1. Active Transport

    Konsentrasi calcium di usus rendah

    Mainly in duodenum and proximal jejenum

    Has limited capacity, and it is controlled through the action of Vit D

    2. Passive transfer

    Konsentrasi calcium di usus rendah

    Independent of vit D

    Sepanjang usus halus

  • Calcium dapat juga diabsorsi dicolon tapi

    dlm jumlah kecil .

    Calcium diabsorsi dlm bentuk ion

    Calcium tidak dapat diabsorsi jikan ada

    oxalate or if it forms soap with free fatty

    acids. Calsium yg tidak diabsorb di

    buang via feces as calcium oxalates and

    calcium soaps

  • Konsentrasi serum ionized calcium di controlled primarily by PTH, hormone ini dikeluarkan oleh parathyroid glands. Dan hormon lainya calcitonin, Vit D, estrogens and other.


    Calcium di tulang akan selalu menyeimbangkan dg calsium dlm darah. PTH mengatur ca serum selalu normal , yaitu 10 mg/100 ml of blood serum (2,5 mmol/L).

    Ketika ca serum darah rendah , PTH stimulates ca tulang ke darah.

    Dalam waktu yang sama PTH promotes renal tubular resorption of calcium, and it indirectly stimulates increased intestinal absorption of calcium via the hormonal form of vitamin D (1,25[OH]2D3)


    Hormon yang lain spt : glucocorticoids, thyroid hormones, and sex hormones juga berperanan dlm calcium homeostatis

    Glucocorticoids berfungsi calcium absorption secara active and passive mechanism

    Thyroid hormones (T4 and T3) stimulates resorption bone; conditions chronic hyperthyroid result in loss of compact and trabecular bone.

  • In woman, normal bone balance memerlukan

    serum konsentrasi estrogen agar kondisi

    normal .

    Kecepatan penurunan serum estrogen

    concentration selama menopause

    merupakan faktor contributing to bone

    resorption. Treating postmenopausal women

    with estrogen slows the rate of bone

    resorption. Bone resorption dihambat by



    CALCIUM (lanjutan)

  • Interactions

    Phosphate: calcium excretion in the urine

    Caffeine: urinary and fecal excretion of calcium

    Sodium: sodium intake, loss of calcium in urine

    Dietary constituents: Phytic acid can reduce

    absorption of calcium by forming an insoluble salt

    (calcium phytate)

    Iron: calcium might have inhibitory effect on iron


  • Absorption and excretion Usual intakes is 1000 mg/day

    About 35 % is absorbed (350 mg/day) by the intestines

    Calcium remaining in the intestine is excreted in the feces

    250 mg/day enters intestine via secreted gastrointestinal juices and sloughed mucosal cells

    90 % (900 mg/day) of the daily intake is excreted in the feces

    10 % (100 mg/day) of the ingested calcium is excreted in the urine

    Calcium must be in a soluble and ionized form before it can be absorbed

  • Absorption and excretion

    factors Absorption increased by: - Body need

    - Vitamin D

    - Protein

    - Lactose

    - Acid medium

    Absorption decreased by: - Vitamin D deficiency

    - Calcium-phosphorus imbalance

    - Oxalic acid

    - Phosphorous

    - Dietary fiber

    - Excessive fat

    - High alkalinity

    - Also stresses and lack of exercise

    Excretion increased by: - Low parathyroid hormone (PTH)

    - High extracellular fluid volume

    - High blood pressure

    - Low plasma phosphate

    - Metabolic alkalosis

    Excretion decreased by: - High parathyroid hormone

    - Low extracellular fluid volume

    - Low blood pressure

    - High plasma phosphate

    - Metabolic acidosis

    - Vitamin D3

  • Metabolism

    Factors involved in calcium metabolism

  • Bone Growth and Calcium


    Figure 23-19: Bone growth at the epiphyseal plate

  • Calcium Metabolism:

    Figure 23-20: Calcium balance in the body

  • Regulation Vitamin D, parathyroid hormone and calcitonin

    Vitamin D (in active form)

    - Berefek pada peningkatan absorbsi ca dan phospat pd intestine

    and kidneys ke dlm cairan extracellular.

    - Sangat berefek pd bone deposition and bone absorption

    Parathyroid hormone (PTH)

    - Meningkatkan mechanism controlling extracellular calcium and

    phosphate concentrations dg cara mengatur reabsorbsi di intestinal

    , renal excretion and perubahan diantara cairan extracellular and

    bone dari dua ions

    Calcitonin (a peptide hormone secreted by the thyroid gland)

    - Cenderung decrease concentration plasma calcium

    - In general, mempunyai efek yg berlawanan thd PTH.

  • Regulation

    Activation of vitamin D3

    - Cholecalciferol formed in the

    skin by sun

    - Converted in liver

    (feedback effect)

    - 1,25 DHCC formation in kidney

    - Controlled by PTH

    - Plasma calcium

    concentration inversely

    regulates 1,25 DHCC

  • Regulation

    Kondisi jika konsentrasi plasma ionized calcium menurun akan dimediasi oleh PTH & vitamin D

    PTH regulates through 3 main effects: - By stimulating bone resorption

    - By stimulating activation of vitamin D intestinal Ca reabsorption

    - By directly increasing renal tubular calcium reabsorption

  • Calcium and the Cell

    Translocation across the plasma membrane

    Translocation across the ER and mitochondrion; Ca2+ ATPase in ER and plasma membrane

  • Phosphor 700 g phosphorus ada pd jaringan, dan

    85% ada pd skeleton and teeth dlm bentuk calcium phosphate crystals.

    The serum inorganic phosphorus diatur PTH at 3 to 4 mg/100 ml in adults

  • Figure 5-3 Phosphorus Balance is maintained primarily by the amount of phosphate absorbed versus the amount excreted by the kidneys and intestine

  • Semua Phosphates di absorbed dlm bentuk inorganic state

    Ikatan Organically phosphate dihidrolisis di lumen intestine dan selanjutnya di keluarkan