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41 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Insulin receptor (4 steps)
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tyrosine kinase
phosphorylates IRS which activates PI3-kinase and Shc activated the Ras-MAP kinase pathway |
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PI3-K reaction
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leads to phozs of downstream kinases
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Akt leads to...
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increased Glut4 in plasma membrane
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some cases insulin can....
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activate phosphateses which de-phos metabolic enzymes
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Glucagon and epinephrine receptors...
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are GPCR
increase cAMP levels |
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Insulin is a
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prepro enzyme
pre is cleaved in ER C-peptide removed by proteases. |
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Secretion of insulin (5)
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1- Glu goes to beta cell by Glut2 and the phozsed by glucokinase.
2- Glucose metabolism increases ATP 3- ATP closes K channel 4 Opens voltage gated Ca++ channels 5- Influx of Ca activates kinases which phozs stuff leading to release of insulin |
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Insulin causes
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tyrosine kinase to phosphorylate IRS and Shc
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IRS binds
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phosphatidylionsitol 3-kinase PI3-kinase
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PI3- kinase consists
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of p110 catalytic subunit and p85 reg subunit
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p85 reg does
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binds to phosphotyrosine of IRS which activates the p110 subunit
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p110 products
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are inositol lipids
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the inositol lipids
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activate enzymes including Akt.
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Akt increase
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movement of Glut 4 transporter to surface of adipose and muscle cells
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insulin signaling ALSO activates
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PP-1 which de phozs Gsk-3
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GSK-3
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blocks glycogen synthesis, and is inhibited by insulin so glycogen synthesis goes up
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Akt ALSO activates
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p70 which promotes protein synthesis
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Shc...
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activates mitogen activated protein kinase pathway that starts cell growth and differentiation MAP K pathway
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Target organs for insulin
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Liver
Adipose tissue Muscle |
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Insulin in the liver...
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INCREASES- Glycolysis, fatty acid synthesis, TAG synthesis, VLDL synthesis, glycogen synthesis, protein synthesis
DECREASES- gluconeogenesis, fatty acid oxidation, glycogen breakdown |
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Insulin in adipose tissue....
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INCREASES glycolysis, fatty acid synthesis, TAG, TAG uptake from chylomicrons, VLDL
DECREASES- TAG hydrolysis |
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Insulin in the muscle
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INCREASES- glycolysis, glycogen synthesis, protein synthesis
DECREASES- glycogen breakdown |
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Glucagon is
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29 AA long peptide
released from pancreatic alpha cells goes to liver and fat tissue |
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glucagon receptor
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is 7 transmembrane G coupled (GPCR)
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alpha subunit of G protein
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coupled to GPCR and glucagon receptor GalphaS. It catalyzes dissociation of GDP from GalphaS and binds GTP
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GTP bound GalphaS
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dissociates from beta and gamma and stimulates adenylate cyclase.
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adenylate cyclase
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ATP to cAMP
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cAMP binds to
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protein kinase A PKA
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PKA
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phozs transcription factor called cAMP response element binding protein CREB
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CREB
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regulates expression of metabolic enzyme genes.
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Metabolic effects of glucagon in liver
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INCREASE- gluconeogenesis glycogenolysis fatty acid oxidation
DECREASE- glycolysis glycogen synthesis fatty acid synthesis |
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met effects of glucagon in adipose tissue
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INCREASES TAG hydrolysis
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Adrenal cortex
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cortisol
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adrenal medulla
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epinephrine
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Epinephrine binds ALSO
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to GalphaS and increases cAMP levels(overlap with glucagon)
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NOTE: they do not bind to each other's receptors and and EPI receptors on muscle and they are similar but not the same to glucagon in liver
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Met effects of epi in muscle
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increase glycogenolysis and glycolysis
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Singulair
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Montelukast
mon-te-LOO-kast |
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Cortisol in fat
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TAG hydrolysis
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cortisol in muscle
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proteolysis
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cortisol deficiency
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addison's disease
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chronic stress
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decrease in muscle loss
redistribution of fat to abdomen |
FFA not oxidized but deposited as visceral fat
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