Biochem Hormone Action 3 Flashcards
What is the growth hormone pathway
Protein Tyrosine Kinase
Kinase on a separate protein and signals thorugh JAK-STAT pathway
Growth hormone is released form teh pituitary and is important for growth periods of mammals, sucha s puberty
Describe how receptors with tyrosine kinase activity have oncogenic potential
Many tumors and tumor cell lines coexpress GF and their recpetors in incresednubers
PDGF and paltelet dreived growth factor
What is Her 2/neu
oncogene, correlation between extend of oer-expressino and prognioss for five year survival
an EGF receptor-like molecula
It is a funcitonal tyrosine kinase
What forms NO
arginine, oxygen, and NADPH by enzye NO synthase (NOS)
What is NO used for?
NS, SM, Macrophage
What ar eth three type sof NOS that are known
nNOS- neuronal
eNOS-endothlial
iNOS-macrophages
What is nNOS?
In postynaptic regions of the brain
What is nNOS activated by?
Ca2+ /Calmodulin in response to NMDA oepnign o postynatpic Ca cahnnels
nM levels of NO increse as the level of cGMP (through guanyl cyclase) and also diffuse back to presynaptic neuron and are invovled in long term potentiation
What is eNOS?
in endothelial vascular membranes
What activates nNOS
ca/calmodulin in response to Ach or Bradykinin activatin of Ca channels
what does nM eNOS cause (2 things)
- NO diffuses into the lumen to prevent platelet aggregation and thus reduce clotting
- NO diffuses back to teh vascular SM to increase cGMP which lowers Ca2+ levels that then causes dilation of the vessel and ultimately lowers BP.
WHat is iNOS
expression of NOS in macrophaages (and also in SM. Inducible in response to cytoking stimulation but this NOS is NOT activated by Ca/Calmodulin
what happens if NO is at high uM concencrations gnerated by Macropahgs
NO is a free radical and can oxidize the metal centers of various metalloenzymes
used by macrophage to attack foreign material sor cells, including tumors
Hormones that use cyclic AMP as a 2nd messenge
Calcitonin -chorionic gonadotropin -ACTH -epinephrine (adrenaline, beta adrenergic receptor) -Follicle-stimulating hromeone -Glucagon -Lipotropin -LH -MSH -Noreprinephrine (NE) -PTH -TSH -Vasopressin -muscuranic Ach -calcitonin -Somatostatin -Beta-adrenergic catecholamines CRH -alpha-2 catecholamines
Hormones that use Ca or Phosphatdidylinositides (or both)
alpha-1 adrenergic catecholamines Cholecystokinin Gastrin TRH Vasopressin Ach (muscrarinic) Antiotenssein II GnRH
Efects mediated by phosphoionisitde cascade
Glycogenolysis in liver cells
Histamine secretion by mast cells
Serotonin release by blood paltelets
Aggregation of blod plaetlets
Insulin secretion by pancreatic islet cells
Epinephrine secretion by adrenal chormaffin cells
SMooth muscle contraction
Visual transcdciton in invertebrea phoreceptors
Wha is spinocerebellar Ataxia 14
Ataxia-inabilityt o coordinate muscular movement
A disease of Protein Kinase C-gamma
16 of 22 cases have a mutation in teh C1 domain that prevents the enzyme tfrom binding to the membrane
PKC can no longer phospphorylate one of its substrates, TRP Ca2+ channel
Neurons can no longer regulate Ca2+ concentration
How are anabolic steroids mediated?
Anabolic effect of AASs is mediated mprimarily by androgen receptors (ARs) in skeletal muscle.
ARs regulate transpcriton of target genes that control expression required for muscle growth
Why does cholear toxin lead to dairrhea
stimulates salt and water secretion into the GI tract, leading to diarrhea
Why does treating cholera toxin with saline not work?
massive loss of ECF can lead to death.
Administration of saline solution orally doesn’t replace the salt lost as a result of toxin. The salt is not absorbed rapidly without glucose as a co-transporter
Electrolyte balance is maintained by oral administration of a salt plust glucose solution (99 mM Na+, 74 mM Cl-, 29 mM HCO3=, 4 mM K+)
Hormones that use cyclic AMP as a 2nd messenge
Calcitonin
- chorionic gonadotropin
- ACTH
- epinephrine (adrenaline, beta adrenergic receptor)
- Follicle-stimulating hromeone
- Glucagon
- Lipotropin
- LH
- MSH
- Noreprinephrine (NE)
- PTH
- TSH
- Vasopressin
- muscuranic Ach
Hormones that use Ca or Phosphatdidylinositides (or both)
alpha-1 adrenergic catecholamines Cholecystokinin Gastrin TRH Vasopressin Ach (muscrarinic) Antiotenssein II GnRH
Efects mediated by phosphoionisitde cascade
Glycogenolysis in liver cells
Histamine secretion by mast cells
Serotonin release by blood paltelets
Aggregation of blod plaetlets
Insulin secretion by pancreatic islet cells
Epinephrine secretion by adrenal chormaffin cells
SMooth muscle contraction
Visual transcdciton in invertebrea phoreceptors
Wha is spinocerebellar Ataxia 14
Ataxia-inabilityt o coordinate muscular movement
A disease of Protein Kinase C-gamma
16 of 22 cases have a mutation in teh C1 domain that prevents the enzyme tfrom binding to the membrane
PKC can no longer phospphorylate one of its substrates, TRP Ca2+ channel
Neurons can no longer regulate Ca2+ concentration
Whaat is the insulin, GH, and IGF-1 connection?
Direction action of GH on lipid, carbohydrate, and protein metabolism–anabolic
IN hypoglycemia, GH stimulates lipolysis, and induces peripheral resistane t insulin, tehreby stimulating use of FA and sparing glucose for the brain.
Why weren’t serum levels of GH measured direction?
Human pituitary coantians about 10mg of GH
5% is released each day in bursts over 3-4 hours. 100x hnage in serum concentration. Highest release is during sleep. Therefore, tehre is no constant measurable GH level.
GHRH and somatostatin form teh hypothalamus control GH release, as well as the IGF-1 inhibitory feedback loop
what does GH stmulate during hypoglycemia
GH stimulates lipolysis and induces preipheral resistance ot insulin, thereby stimulating use of FA andsparing glucose for brain.
