Mekanisme Kerja Hormon

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Mekanisme Kerja Hormon. Hormone Action. The action of a hormone : efek primer pada sel ( ikatan hormon – reseptor spesifik): hormone–receptor complex complex → effector system → signal transducing mechanism → biochemical process(es) within the cell. intracellular receptor. - PowerPoint PPT Presentation

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Mekanisme Kerja HormonHormone ActionThe action of a hormone: efek primer pada sel ( ikatan hormon reseptor spesifik): hormonereceptor complexcomplex effector system signal transducing mechanism biochemical process(es) within the cell.

intracellular receptor

Complex activates a gene (transcription factor)

The DNA sequences of severalhormone response elements (HREs)

Transmembrane Receptors. The signal activates a channel, an enzyme, or a G-protein cascade.Enzyme coupled receptors: Signal activates an enzyme activity of the receptor itselftyrosine kinases, phospholipase C.G-protein coupled receptors: Signal activates a G-protein that activates downstream enzymesmakes second messenger(cAMP or Ca2).Ion-channel coupled receptors: Signal activates an ion channelEffector systemsHormonereceptor complex: meningkatkan aktivitas enzimG-proteinion channelgene

Hormonereceptor complex: meningkatkan aktivitas enzim protein kinase

PROTEIN KINASESTransmembrane receptor kinases : tyrosine kinase ATP : phosphorylate specific tyrosine enzymatic (amplification step). serine/ threonine protein kinases ATP to phosphorylate specific serine or threonine.phosphorylation cascades :one kinase phosphorylates another MAP kinase kinase kinase. (mitogen-activated protein kinase that phosphorylates MAP kinase kinase).

Membrane-bound phospholipaseHydrolisa: phosphatidylinositol bisphosphate (PIP2) dua messenger , inositol trisphosphate (IP3) diacylglycerol (DAG)example: adrenaline binding to the -receptor in the liver: Ca2+ ions stimulate glycogenolysis

glycogen synthase in muscle

Enzymes and proteins regulated bycalcium or calmodulin.Adenylyl cyclaseCa2+-dependent protein kinasesCa2+-Mg2+ ATPaseCa2+-phospholipid-dependent protein kinaseCyclic nucleotide phosphodiesteraseSome cytoskeletal proteinsSome ion channels (eg, L-type calcium channels)Nitric oxide synthasePhosphorylase kinasePhosphoprotein phosphatase 2BSome receptors (eg, NMDA-type glutamate recept

Gomplex activates G-proteinH-R complex: activates G-protein activates a membrane-bound enzyme (e.g. adenyl cyclase, which converts ATP to cyclic AMP).

G-Protein

Pathway of glycogenesis and of glycogenolysis in the liver

Control of adipose tissue lipolysis.

Cyclic GMPCyclic GMP: is made from GTP by the enzyme guanylyl cyclase (activate : atrial natriuretic factor)

Control of phosphorylase in muscle.

glycogen synthase in muscle