BCHM: Hormone Signaling Pathways Flashcards
Which hormones are water soluble (hydrophilic)?
Epinephrine, Insulin, Glucagon, GH
CANNOT PENETRATE MEMBRANE
Which hormones are lipid soluble (hydrophobic)?
Estrogen, Testosterone, Cortisol, 1,25-dihydroxy cholecalciferol
What are the two types of estrogen receptors?
ER alpha
ER beta
Where are ER alpha receptors found?
Female reproductive tract
Females = alpha always
uterus, vagina, ovaries, mammary gland, hypothalamus, endothelial cells, vascular smooth muscle
Where are ER beta receptors found?
Ovaries + Prostate
and lung, bone, brain, vasculature
*many cells express both receptors*
Estrogen, is an example of a nuclear receptor. How does it activate transcription via the GTA (general transcription apparatus) ?
Stimulates histone acetyl transferase (HAT)
Tamoxifen is a breast cancer treatment that is an antagonist of the nuclear estrogen receptor. How does it accomplish this?
It is metabolized by the liver Cyt P450 –> 4-hydroxy-tamoxifen
This promotes histone deacetylase (HDAC) which inhibits transcription of estrogen
What are the 3 domains of nuclear receptors?
- LBD
- AF1
- DBD
What enzyme can lead to Insulin Resistance?
Ser/Thr Kinase –> phosphorylates serine and inhibits tyrosine + IRS activation
It is activated by cytokines, FFA’s, DAG, ceramide, + inflammatory molecules
What receptors are hydrophilic + main hormones?
GPCR’s (Epi) + RTKs (insulin)
What receptors are hydrophobic?
Nuclear (estrogen) + Cytoplasmic
Gs stimulates _______. Signal?
adenylate cyclase
signal = epi, beta adernergic receptors, histamine
Gt stimulates ________. Signal?
cGMP phosphodiesterase
signal = light
Gi inhibts ______. Signal?
Adenylate cyclase
Signal = Epi/NE, alpha adenergic receptors, dopamine
Gq stimulates _________. Signal?
Phospholipase C
signal = ACh
