Mechanisms of Hormone ActionBy:

Mohamed Issam, Mohamed Elshafiei, Mohamed Hany

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Types of hormonal Action:

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Examples of hormones by action:

Figure 45.6-1

Lipid-solublehormone

SECRETORYCELL

Water-solublehormone

VIABLOOD

Signal receptor

TARGETCELL

(a) (b)

Signalreceptor

Transportprotein

NUCLEUS

Figure 45.6-2

Lipid-solublehormone

SECRETORYCELL

Water-solublehormone

VIABLOOD

Signal receptor

TARGETCELL OR

Cytoplasmicresponse Gene

regulation

(a) (b)

Cytoplasmicresponse Gene

regulation

Signalreceptor

Transportprotein

NUCLEUS

Obvious answers aren’t always so

simple

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1. Adenylate cyclase System:

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2. Intracellular Ca++ A) Open Ca++ channel

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B) Increase intracellular Ca++ through IP3:

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Fate of the increased Ca++:

3.Tyrosine Kinase system

JAK = Janus family of receptor-associated tyrosine kinase Growth hormone (GH) action: Targets of JAK include signal transducers and activators of transcription (STAT),which cause transcription of new mRNAs and new protein synthesis.

Figure 45.8-1

EXTRACELLULARFLUID

Hormone(estradiol)

Estradiol(estrogen)receptor Plasma

membrane

Hormone-receptorcomplex

EXTRACELLULARFLUID

Hormone(estradiol)

Estradiol(estrogen)receptor Plasma

membrane

Hormone-receptorcomplex

NUCLEUS

DNA

CYTOPLASM

VitellogeninmRNA

for vitellogenin