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biosintesis hormon
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HORMONE SYNTHESIS, RELEASE AND TRANSPORT
The hormones speak :We are the chemical messengers of the body.Diversified in our structure and function;Act either directly or through messenger;Growth, health, and welfare is our motto
Hormone:produced in small amounts by specific tissues (endocrine glands), control the metabolic and biological activities in the target cellsHormone
HORMONE CLASSIFICATION
Protein and polypeptideAmineSteroidEicosanoid
BIOCHEMISTRY MEDICAL FACULTY USU
BIOCHEMISTRY MEDICAL FACULTY USU
PEPTIDE HORMONESConsist of specific amino acidsSynthesized as large precursor proteinsStored in membrane-enclosed compartmentsHydrophillic
PEPTIDA INSULIN
Di sintesa di Pulau Pankreas sebagai preproinsulinUntuk sekresi disimpan di RES oleh enzim mikrosomal dibelah menjadi proinsulin sewaktu memasuki membran RESProinsulin diangkut ke golgi kompleks dikemas menjadi secretory granulesDi granula, C-Peptida dipisahkan insulin disekresikan
Protein and Polypeptide Hormones Synthesis: Peptide hormone synthesis and packaging
ProinsulinInsulin
AMINE HORMONESDerived from the amino acid tyrosineIncludes thyroid hormones and catecholaminesStored until secreted
Thyroid gland produce T3 and T4 hormonesIodide (I-) actively transported into the follicle of thyroid gland Oxidized to iodine (Io) by a peroxidaseThyroid Hormones
Iodine attached to tyrosine within thyroglobulin chain MIT, DITMIT and DIT or 2 DIT molecules coupled togetherTSH via cAMP stimulates hydrolyze T3 and T4 from thyroglobulin (inhibited by KI)Thyroid Hormones
STEROID HORMONESPrecursor: CholesterolLipophillicImmediately released from the cell following synthesis
Hormon Steroid
Korteks adrenal sintesis :glukokortikoid, mineralokortikoid, sex steroidTerutama dari kolesterol plasma (sebahagian kecil dari asetil koA)Kolesterol plasma dirubah menjadi pregnenolon oleh enzim sitokrom P450 (mitkondria atau RES)
Hormon Steroid
Hormon Steroid
Kekhususan seluler :sintesis mineralokortikoid pada sel glomerulosa 18 hidroksilase dan 18 hidroksisteroid dehidrogenase hanya ditemukan pada sel ini
Golongan Hormon Steroid
Protein TransportThyroid Hormones Globulin alfa (85%)TBG TBPA (transferitin) Albumin sedikit
Protein TransportHormon Steroid
Kortisol- 75 % terikat CBG (transkortin)- 10 % kortisol bebas- selebihnya pada albumin (mis deksametason)
Protein TransportHormon Steroid
Androgen- DHEA terikat lemah pada albumin- Testoteron terikat pada globulin spesifik ( SHBG)Mineralokortikoid- tidak punya protein pengangkut spesifik- membentuk ikatan lemah dengan abumin
EICOSANOIDS HORMONEProduced from arachidonic acid, Released from phospholipids by action of phospholipase A2, phospholipase C Produced in almost every organIn one pathway arachidonic acid is converted to prostanoids by a group of enzymes, the cyclooxygenase systemA second pathway to produce leukotrienes by the enzyme 5 lipoxygenase
EICOSANOIDS HORMONE
Prostaglandins
SAIDS inhibit action of phospholipaseNSAIDs, such as aspirin and derivatives of ibuprofen, inhibit cyclooxygenase activity of PGH2 SynthaseThey inhibit formation of prostaglandins involved in fever, pain, & inflammationThey inhibit blood clotting by blocking thromboxane formation in blood platelets
REFERENCESDevlin T M, PhD. Text Book of Biochemistry with Clinical Correlations 5thed. Wiley-Liss, New York. 2002 : 906-952, 982-983McKee Trudy, McKee James R. The molecular basis of Life. 3rded. McGraw-Hill. Americas, New York. 2003 : 541-559Murray R K, et al. Harpers Biochemistry 26thed. Appleton & Lange. America 2003: 434-473Raff A, et al. Moleculer Biology of The Cell. 4thed. Garland Science. New York. 2002: 832-892Stryer L. Biokimia. Edisi 4. EGC, Jakarta. 2000.: 340-358
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