Mekanisme Kerja Hormon dr Susila Sastri M Biomed

Mekanisme Kerja Hormon dr. Susila Sastri M. Biomed Biokimia FK-Unand

Hormone

Struktur Kimia Hormon 1. Polipeptida • Insulin • Glucagon 2. Derivat asam amino (amin) • Epineprin • Serotonin • Tyroxin 3. Steroid (derivat kolesterol) • Aldosteron • Cortisol • Retinoic acid 4. Eicosanoid (polyunsaturated • acid, (20 atom C) • Prostadglandin E • Thromboxane A 2

Simple Intracellular & Extracelluler Signaling

Hormon Action

Hypophise Anterior

Neurohormone

Cell Communication GAS MOLECULE

Second messenger: Small molecules synthesized in cells in response to an external signal are the second messengers, which are responsible for intracellular signal transduction: Ca 2+, DG, Cer, IP 3, c. AMP, c. GMP

Receptors: specific membrane proteins, which are able to recognize and bind to corresponding ligand molecules, become activated, and transduce signal to next signaling molecules: A. Membran B. Intra Sel Glycoprotein or Lipoprotein

Kelenjer-Hormon-Target Sel Releasing hormones Hypothalamus Nervous Anterior pituitary Posterior pituitary Thyrotropin Somatotropin LH ACTH Thyroid T 3 Adrenal Cortex FSH Pancreas Ovary Vasopressin Prolactin Adrenal Medulla Testis Cortisol Insulin, Estradiol Testosterone aldosterone glucagon, somatostatin Muscles Tissues liver Liver, muscles Reproductive organs Oxytocin Epinephrine Mammary glands

1. Membrane receptors

Signal transduction mediated by membrane receptor • c. AMP dependent-protein kinase A pathway • c. GMP dependent PKG pathway • Ca 2+ dependent PK pathway • Tyrosine protein Kinase pathway • NF-κB pathway • TGF- βpathway

Membrane Receptor

Cyclic AMP

Mekanisme Signal Tranduksi

Hormon-2 nd Massengger- Enzim 1 2 3 Nitric oxide T-cell Activation Glucagon 1 3 2 G G protein Cyclic AMP G Cyclic GMP PK-A PK-G G 4 IP 3 G Diacylgycerol Calmodulin PK-C Multifunctional kinases Protein substrates Insulin 5 Ca 2+ Protein substrates End result is phosphorylation of one or more proteins 5 4 Tyrosine Protein kinase substrates Protein Ser/Thr kinases Protein substrates Other phospholipases

Inositol triphosphate System PLC; phospholipase C PIP 2: phosphoinositol DAG: diacylgliserol IP 3: inositol triphosphat PKC: phosphokinase C

Intracellular receptor (DNA transcription regulated receptor) Steroid Hormone, VD 3, Thyroxine • Cytosolic R: glycocorticosteroid H • Nuclear R: thyroxine, estrogen, androgen, progesterone

Hormon - Receptor • highly specificity • highly affinity • saturation • reversible binding • special function model

Control of receptor activity • Phosphorylation or dephosphorylation of R • Phospholipid of membrane • Enzyme catalyzed hydrolysis • G protein regulation