Heck hormone synthesis and signaling Flashcards
What are the classes of hormones
proteins, polypeptides
steroids
amines
What is the largest class of proteins
hormones
What is the general secretory pathway for protein hormones
Nucleus rER sER golgi exocytosis
What is the difference between constituitive and regulatory pathways
constituitive- involves ECM and plasma membrane components
REgulated- hormones and enzymes regulated at level of transcription or exocytosis
steroids are synthesized from cholesterol how
from LDL in blood or de novo from acetyl-CoA
cholesterol is converted to the universal precursor, prenenolone
Describe structure of steroid hormones
lipophilic
What regulate steroid hormones
trophic hormones from pituitary
no intracell stores of hormone
synthesis and secretion closely linked
What 2 tissues create protein hormones
adrenal cortex and gonads
What protein hormones does the adrenal cortex create
cortisol synthesis
aldosterone
androgens
what type of corticoid is aldosterone
minerlocoritcoid
What protein hormones do the gonads secrete
ovary- estrogen or progesterone
testes- testosterone
What is the origin of amine hormones
tyrosine
what does dopamine turn into
tyrosine->DA->Ne->epi
Know that dopamine acts as a NT and catecholamine too
Ok
What do follicular cells of thyroid gland secrete into lumen
iodine and thyroglobulin
Where does proteolysis of T3 and T4 from thyroglobulin take place
endolysosome
Where is noreepi and eli synthesized and stored
chromaggin granules
What simtulates release of norepi and epi
SAN
control centers for catecholamines detect what
end physiologic effect via BP (stretch R)
How form do circulating hormones exist as
free or unbound
short term or quick acting
water soluble
What hormones are water soluble
peptides and catecholamines
Describe the characterisitics of hormones that are associated with binding proteins
long term, slow acting
fat soluble
What type of hormones are fat soluble
steroid and thyroid hormones
Describe difference of thyroid hormones because bound to thryoglobulin
extends half life and creates reservoir for blood
Describe R for protein hormones
GPCR on cell surface coupled to cAMP phospholipase C and A2
Describe the coupling to cAMP via GPCR
G proteins activates or inhibits adenyl cyclase, which modulates cAMP which acts on PKA to phosphorylate substrates
Describe coupling of Phospholipase C to GPCR
G protein activakes PLC which cleaves PIP2 to IP3 and DAG
IP3 releases ER Ca stores and activates Ca induced kinases like PKC
DAG activates PKC
describe coupling of phospholipase A2 to GPCR
activates G protein which results in activation of PLA2 which cleaves membrane phospholipids to produces lysophospholipid and arachidonic acid
aa converted into eicosanoids
Describe the activation and result of guanylyl cyclase
R itself is a guanylyl cyclase increasing intracell cGMP
Describe mech of R tyrosine Kinase
initiates intracell cascade of Pi
R may autophosphorylate themselves
R may Pi cytoplasmic tyrosine kinases (Tyrosine-kinase associated R)
What type of R do steroid hormones usually bind
intracell receptors, cytosolic or nuclear
What are hormone response elements
when steroid R activate they dimerize and bind 5’ DNA sequences and initiate transcription
What can cause dissociation of steroid R
chemical modifications that change confirmation
Is receptor expression induced by steroid hormone itself
no
What type of R do amine hormones bind to
cell surface R
What does the intracell effect of amine hormones rely on
combination of R present
describe types of amine hormones
adrenoreceptors
dopamine receptors
What are the alpha adrenergic R
G protein inhibitory via alpha 2
alpha 1 coupled to phospholipase C which activates G protein that activates PLC–> PIP2–>IP3 and DAG
induces PKC
What NT mainly acts on alpha adrenergic R
norepinephrine
What NT mainly acts on beta adrenergic R
epinephrine
What type of pathway do the beta adrenergics stimulate
G protein stimulatory
What are the dopaminergic R
GPCRs
DA-1
DA-2
Is DA-1 stimulatory? DA-2?
DA-1 is G protein stimulatory
DA-2 is G protein inhibitory
Thyroid hormone is most similar to what other hormones
steroid
Where is the thyroid hormone R
in the nucleus
What occurs when T3 binds thyroid hormone Receptro
dimerizes with retinoid X receptor
Binds HREs to initiate transcription
stopeed on slide 27
G proteins and 2nd messengers
