Metabolism review (1.2) Flashcards
What is the most important hormone in the fed state?
Insulin…in DIRECT response to GLUCOSE
What would this mean after a high protein/low carb meal?…less insulin and more glucagon
What does insulin activate?
Phosphatases…removes phosphate groups
What is the downstream effect of insulin on Glycogen Synthase Kinase 3 (GSK3)?
Dephosphorylation –> activation –> synthesizing glycogen
Makes sense to create energy storage in the fed state
What is the downstream effect of insulin on Protein Phosphatase 1 (PP1)?
Dephosphorylation –> inactivation –> does NOT break down glycogen storage
Makes sense to not deplete energy storage in the fed state
What signaling pathway does insulin activate that leads to increased transcription?
MAPK cascade…in this case it’s activating kinases
What happens in the liver during the fed state?
Glucose producing pathways are inhibited
Glucose storing pathways are activated
What happens in the brain during the fed state?
Oxidizes glucose via ETC
What happens in the RBCs during the fed state?
Fermentation of pyruvate –> lactate
No mitochondria = No ETC
Makes sense to not have RBCs use up the O2 they are supposed to be bringing around for other cells to use
What happens in white adipose cells during the fed state?
Ferments glucose to glycerol 3-phosphate
Uses as a backbone for triacylglycerol synthesis
What happens in skeletal muscle during the fed state?
Glycolysis
Fatty acid beta-oxidation
Glycogenogenesis
Protein synthesis
What happens in cardiac muscle during the fed state?
Fatty acid beta-oxidation (60-80%)
Oxidation of glucose –> lactate (20-40%)
What happens in intestinal epithelial cells during the fed state?
Conversion of glutamate, glutamine, and aspartate (from the diet) –> alpha-ketoglutarate (for TCA cycle)
What happens in colonocytes during the fed state?
Use short chain fatty acids produced by gut bacteria
What is the primary hormone during the fasted state?
Glucagon (from pancreas alpha cells)
What kind of receptor does glucagon bind to? what is the downstream effect?
GPCR
Think phosphorylation
What happens in the liver during the fasted state?
Glycogenolysis
Gluconeogenesis
Where does the energy required for gluconeogenesis come from?
Fatty acid beta-oxidation
FADH2/NADH –> ATP
Besides FADH2 and NADH, what else is made during FA beta-oxidation? How is it used?
Acetyl CoA
Ketone body synthesis (in the liver)…brain energy
What happens in skeletal muscle during the fasted state?
Proteolysis
If a persistent fast…may use ketone bodies for energy
Which amino acids are used for fuel by muscles in the fasted state?
Branched chain amino acids (leucine, isoleucine, valine)
Which amino acids are used fro gluconeogenesis?
Alanine (–> pyruvate)
Glutamine (–> alpha-ketoglutarate)
What happens in cardiac muscle during the fasted state?
FA beta-oxidation increases
Glycolysis decreases…but isn’t shut off
What happens in the gut during the fasted state?
Glutamine from BLOOD for energy
What happens in white adipose tissue during the fasted state? What are the products used for?
Lipolysis
FAs (fuel for heart and liver)
Glycerol (gluconeogenesis in the liver)
What is the primary source of fuel in the starved state?
Fatty acids (increased lipolysis)
Proteolysis and gluconeogenesis are DECREASED
What does cardiac muscle use as an energy source during the starved state?
Fatty acids (heart uses FAs…remember that)
Does not like using ketone bodies
What is the effect of epinephrine during hypercatabolism?
Activates hormone sensitive lipase
Smaller player
What is the effect of cortisol during hypercatabolism?
Activates muscle proteolysis
Bigger player
What is the effect of glucagon during hypercatabolism?
Activates glycogenolysis and gluconeogenesis
