Week 4 Integration of Metabolic Pathways Lecture Flashcards Preview

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Flashcards in Week 4 Integration of Metabolic Pathways Lecture Deck (28):

Can ATP produced in the liver be used in the kidney?

NO. ATP is not transported between cells


PFK-1 role:

converts Fructose-6-phosphate to Fructose-1,6-BP (in glycolysis)


how is PFK-1 regulated?

Allosterically. promoted by AMP or F-2,6-BP. Inhibited by ATP and citrate.


what are examples of catecholamines? where are they produced?

E/NE, adrenal gland


describe E/NE in the liver

1. E/NE binds GPCR on membrane
2. GPCR activates Gs, and G-alpha and G-beta/gamma dissociate
3. G-alpha activates adenyl cyclase which produces cAMP.
4. cAMP activates PKA
5. PKA phosphorylates and activates phosphorylase kinase
6. phosphorylase kinase converts inactive glycogen phosphorylase b to active glycogen phosphorylase a
7. PKA inactivates glycogen synthase
8. glycogen ins broken down


what are the effects of catecholamines on skeletal muscle (4)

1. increase glycolysis
2. decrease glycogen synthesis
3. increase glycogenolysis (degrade glycogen)
4. increase triglyceride utilization


what are the effects of catecholamines on liver (5)?

1. decrease glycolysis
2. increase glycogen breakdown
3. decrease glycogen synthesis
4. increase gluconeogenesis
5. decrease FA synthesis


what are the effects of catecholamines on adipose tissue? 2

1. increase lipolysis (release FFAs, HSL)
2, decrease triglyceride utilization


what explains the differing role in skeletal muscle and liver in response to catecholamines?

both cells have PFK-1 that is promoted by F-2,6-BP. However, the enzyme that produces F-2,6-BP are different in each cell type (isozymes) even though they are both phosphorylated by cAMP-PKA signaling. In the liver, phosphorylation of F-2,6-BPase deactivates the enzyme (less F-2,6-BP, no glycolysis) and in the skeletal muscle phosphorylation of F-2,6-BPase activates the enzyme (more F-2,6-BP and more glycolysis)


Glucocorticoids are produced when?

during chronic stress


what is the overall role of glucocorticoids, how does this compare to catecholamines?

GCs: regulate gene expression and are therefore much slower acting than catecholamines which are immediate fight/flight


how does adipose tissue respond to increased glucocorticoids? 2

increased lipolysis, increased expression of lipases


how does skeletal muscle respond to an increase in glucocorticoids? why/how?

increase protein degradation in peripheral tissues (smaller muscles) due to increased expression of protease enzymes. these non-essential muscles are used to make AA that produce energy


how does the liver respond to increased glucocorticoids?2

increase gluconeogenesis, increase glycogen synthesis


cortisol is an example of a ....



increased chronic stress (increased cortisol) can be thought of as_____ and increased catecholamines can be though of as_____

cortisol: storing energy to prepare for an attack
Catecholamine: using the stored energy


how is alcohol absorbed in our bodies

via simple diffusion in SI and stomach


how is alcohol distributed in our bodies?

alcohol is lipid (small polar) and water soluble (polar) so it can cross membranes and distribute in water-filled environments (except in adipose)


where is alcohol metabolized?



what two systems are used to metabolize alcohol? where within liver cells are these processes located

Alcohol dehydrogenase system (cytoplasm of liver cells), microsomal ethanol oxidizing system (MEOS, ER of liver)


when do we see the microsomal ethanol oxidizing system? what does it require

induced by heavy drinking. NADPH required


What is the main product of alcohol metabolism?



the metabolism of ethanol produces an abundance of...



what issues arise as a result of the increased NADH/NAD+ ratio during alcohol consumption.

An abundance of aceyl-CoA, NADH and ATP causes:
1. glucose metabolism stops (no need for energy, regulated at PFK-1 and PDH)
2. Hyperlidemia: decrease in FA breakdown (no need for energy, decreased NAD) and increased FA storage (TGs) which increase VLDL
3. Hypoglycemia: A decrease in gluconeogenesis due to the formation of lactate (high NADH/NAD) being favored over the formation of glucose from pyruvate/oxaloacetate


what is resveratrol?

cmpd in wine that has shown to extend life in some organsims but not humans


what three molecules are key junctions in metabolism?

G6P, pyruvate, acetyl-CoA


GPP can follow what three pathways?

Pentose phosphate pathway (NADPH, nucleotides), Glycolysis/TCA (pruvate formation), Glycogen formation (G1P)


Pyruvate can be converted to what molecules?4

Oxaloacetate (can feed into gluconeogenesis), Lactate, Alanine, Acetyl-CoA

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