Mechanism of Hormone Action Mechanism of Hormone Action
Receptor Structure Mechanism of Hormone Action
Receptor
Protein Kinase A(PKA)
NucleusDNA
Protein Synthesis(Enzymes)
Plasma Membrane
Protein Hormones(cAMP second messenger)
Protein Hormones(cAMP second messenger)
CR
R-ERProtein Synthesis
Mitochondria
S-ERSteroid Synthesis
LH
G
Adenylate Cyclase
Mechanism of Hormone Action
Receptor
Protein Kinase A(PKA)
NucleusDNA
Protein Synthesis(Enzymes)
Plasma Membrane
Protein Hormones(cAMP second messenger)
Protein Hormones(cAMP second messenger)G
Adenylate Cyclase
CR
cAMP
LH
ATP cAMP
CR
R-ERProtein Synthesis
Mitochondria
S-ERSteroid Synthesis C
RcAMP
Mechanism of Hormone Action
Receptor
Protein Kinase A(PKA)
NucleusDNA
Histones
Protein Synthesis(Enzymes)
Plasma Membrane
Protein Hormones(cAMP second messenger)
Protein Hormones(cAMP second messenger)G
Adenylate Cyclase
LH
ATP cAMP
(+ PO4)
R-ERProtein Synthesis
Mitochondria
S-ERSteroid Synthesis
mRNA
Mechanism of Hormone Action
Receptor
Protein Kinase A(PKA)
NucleusDNA
Histones
Protein Synthesis(Enzymes) mRNA
Plasma Membrane
Protein Hormones(cAMP second messenger)
Protein Hormones(cAMP second messenger)
Cholesterol
GAdenylate Cyclase
C
RcAMP
LH
ATP cAMP
(+ PO4)
R-ERProtein Synthesis
MitochondriaCholesterolPregnenolone
S-ERSteroid Synthesis
Testosterone
Mechanism of Hormone Action
Receptor
Protein Kinase A(PKA)
NucleusDNA
Histones
Protein Synthesis(Enzymes) mRNA
Plasma Membrane
Protein Hormones(cAMP second messenger)
Protein Hormones(cAMP second messenger)
Cholesterol
GAdenylate Cyclase
C
RcAMP
LH
ATP cAMP
(+ PO4)
R-ERProtein Synthesis
MitochondriaCholesterolPregnenolone
S-ERSteroid Synthesis
Testosterone
cAMP Second Messenger Hormones
• Anterior Pituitary Hormones» LH, FSH, Prolactin» STH, ACTH, TSH
• Placental Hormones»HCG, eCG
Protein Hormones (Ca2+ Second Messenger)Protein Hormones (Ca2+ Second Messenger)
PLC
Endoplasmic Reticulum
Ca2+
Protein Kinase C
Plasma Membrane
GnRH
Rece
ptor
G-protein
R
PlasmaMembrane
SecretoryGranules
PIP2
Protein Hormones (Ca2+ Second Messenger)Protein Hormones (Ca2+ Second Messenger)
PLC
PIP2
Endoplasmic Reticulum
Ca2+
Plasma Membrane
GnRH
Rece
ptor
G-protein
R
PlasmaMembrane
SecretoryGranules
PIP2
Protein Kinase C
Protein Hormones (Ca2+ Second Messenger)Protein Hormones (Ca2+ Second Messenger)
PLC
PIP2
Endoplasmic Reticulum
Ca2+
Protein Kinase C
Plasma Membrane
GnRH
Rece
ptor
G-proteinDAG
IP3
R Ca2+
PlasmaMembrane
SecretoryGranules
R
PIP2
Protein Hormones (Ca2+ Second Messenger)Protein Hormones (Ca2+ Second Messenger)
PLC
PIP2
Endoplasmic Reticulum
Ca2+
Protein Kinase C
Plasma Membrane
GnRHRe
cept
or
G-proteinDAG
IP3
R Ca2+
PlasmaMembrane
Ca2+
SecretoryGranules
R
PIP2
Protein Hormones (Ca2+ Second Messenger)Protein Hormones (Ca2+ Second Messenger)
PLC
PIP2
Endoplasmic Reticulum
Ca2+
Protein Kinase C
Plasma Membrane
GnRH
Rece
ptor
G-proteinDAG
IP3
R Ca2+
PlasmaMembrane
Ca2+
LH
Fusion
SecretoryGranules
R
PIP2
Calcium Second Messenger Hormones
• GnRH» triggers release of LH in anterior pituitary
• Oxytocin» triggers contractions of smooth muscle
• PGF2α» triggers apoptosis of cell» inhibition of progesterone synthesis
Steroid Hormone Action
Cytoplasm
Cell Membrane
DNAReceptor
Nucleus
Steroid(estrogen)
Diffusion?
mRNAR-ERProtein synthesis
NewProtein
Change inCell
Physiology
Steroid Hormone Mechanism
• Estradiol• Testosterone, Dihydrotestosterone• Cortisol
FeedbackLoops
Hypothalamus
Releasing Hormones
Neuro-secretory Cells
Portal Vein
Anterior Pituitary
Gonadotropins: FSH, LH
Blood Stream
GonadsReceptor on Cell Surface
Cyclic AMP inside cell
Steroid Hormone Production
Blood Stream
-
-
Polypeptides
Proteins
Why only effects on target organs[ ]
{TestosteroneEstradiolProgesterone
Bound to Protein
Endocrine Feedback Loops
• Negative» gonadal steriods
– Testosterone, Progesterone, Estradiol» Protein hormones
– inhibin
• Positive» Gonadal steroids
– estradiol
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