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Biochemistry - MOD2 - Hormone Action and Metabolism
pgs 54 - 63
37
Chemistry
Professional
10/10/2010

Additional Chemistry Flashcards

 


 

Cards

Term

the major hormones that regulate metabolism are (blank) and (blank)

 

they respond minute-to-minute in response to changes in (blank1)

 

they indirectly provide efficient (blank1) to RBCs and brain by directly altering the metabolic activities of (blank), (blank), and (blank)

Definition

insulin and glucagon

 

blood glucose

 

liver, adipose, and muscle

Term
the following diagram illustrates the changes in blood glucose, and serum insulin and glucagon that occur following a meal
Definition
[image]
Term
a rise in blood glucose increases secretion of (blank) from (blank) cells and decreases (blank) secretion from (blank) cells
Definition

insulin from pancreatic beta cells

 

glucagon from pancreatic alpha cells

Term

insulin is synthesized as a (blank).

 

the pre [or (blank)] is cleaved in the (blank).

 

The Connecting [or (blank1)] is removed by proteases that cleave at pairs of (blank) amino acids as the pro-insulin is processed.

 

The mature insulin is STORED in secretory vesicles with the (blank1) and with the cleaved (blank)s 

 

All are released in response to (blank)

Definition

prepro-peptide

 

signal sequence (pre) cleaved in the ER

 

C-peptide removed by proteases that cleave at pairs of BASIC amino acids

 

C-peptide and cleaved amino acids

 

increased blood glucose

 

 

Term

secretion of insulin in response to glucose involves following pathway:

 

  1. glucose is transported into the (blank) cell by (blank) and then is phosphorylated by (blank).  Both of these proteins can respond to changes in blood glucose that occur during a meal because their Km's (Kd for the receptor - strength of ES interaction) are in the range of blood glucose concentration that occurs after a meal.
  2. Glucose metabolism increases (blank1) levels
  3. (blank1) closes a (blank) channel
  4. This results in the opening of a (blank)
  5. (blank) enters the cell and activates (blank)s which phosphorylate proteins leading to release of (blank)

Definition

beta cell

 

Glut2

 

glucokinase

 

ATP

 

potassium channel

 

voltage-sensitive calcium channel

 

calcium

 

protein kinases

 

insulin

 

 

Term
overview of pathway to initiate insulin secretion
Definition
[image]
Term

Insulin signaling and the metabolic effects of insulin

 

insulin travels through the bloodstream to many target tissues.  Chief among these are (blank), (blank), and (blank).

Definition

liver

 

adipose

 

skeletal muscle

Term

 

Insulin signaling and the metabolic effects of insulin

 

insulin binds to a cell surface receptor and stimulates (blank1) of the receptor [called (blank)]

 

This causes (blank1) of two types of proteins:

  1. (blank)s
  2. (blank)

 

Definition

tyrosine phosphorylation 

 

called AUTOPHOSPHORYLATION

 

  1. insulin receptor substrates (IRS)
  2. Shc

Term

 

Insulin signaling and the metabolic effects of insulin

 

The major effect of IRS phosphorylation is to bind and activate an enzyme called (blank1)

 

This enzyme consists of a (blank) subunit and a (blank) subunit.

 

 

Definition

PI3-kinase 

 

or phosphatidylinositol 3-kinase

 

p110 catalytic

 

p85 regulatory.

Term

Insulin signaling and the metabolic effects of insulin (PI3-kinase has 2 subunits)

 

The p85 subunit binds to (blank) residues of (blank) molecules, resulting in activation of of the (blank) subunit.

 

Definition

phosphotyrosine 

 

IRS (insulin receptor substrates)

 

p110 Catalytic subunit of PI3-kinase

Term

 

Insulin signaling and the metabolic effects of insulin (PI3-kinase has 2 subunits)

 

The products of the p110 catalytic subunit are (blank1)s, which activate enzymes, which in turn result in (blank) of metabolic pathways.

 

One of the most important of these enzymes activated by (blank1)s is (blank), which increases the movement of (blank) to the surface of adipose and muscle cells.

 

Definition

Inositol lipids

 

regulation

 

Akt

 

Glut4 glucose transporters

Term

Insulin signaling and the metabolic effects of insulin

 

insulin signaling often activates a (blank), called (blank), which de-phosphorylates metabolic enzymes, resulting in their activation or inhibition.  

 

(blank1) blocks glycogen synthesis and thus, is inhibited by insulin action.  [(blank1)'s inhibition will stimulate glycogen synthesis.]

 

activation of (blank) promotes protein synthesis

Definition

phosphatase called PP-1

 

GSK-3

 

p70

Term
Insulin signaling diagram
Definition
[image]
Term

Metabolic effects of Insulin - LIVER

 

Increased: ?  (1 catabolic and 5 anabolic mechanisms)

 

Decreased: ? (all catabolic)

 

Definition

Increased 

 

  • glycolysis
  • fatty acid synthesis
  • glycogen synthesis
  • triacylglycerol synthesis
  • VLDL release
  • protein synthesis
Decreased
  • gluconeogenesis
  • glycogenolysis
  • fatty acid oxidation

 

Term

Metabolic effects of Insulin - ADIPOSE

 

Increased: ?? 1 catabolic, 2 anabolic and increase uptake of (blank)

 

Decreased: ?? just one catabolic (think of what happens during fasting state)

Definition

Increased

  • glycolysis (catabolic)
  • fatty acid synthesis (anabolic)
  • Triacylglycerol (TAG) synthesis (anabolic)
  • increased uptake of TAGs from chylomicrons and VLDL
Decreased
  • TAG hydrolysis (catabolic)

Term

Metabolic effects of Insulin - MUSCLE

 

Increased: ?? 1 catabolic, 2 anabolic

 

Decreased: ?? 1 catabolic

Definition

Increased: 

  • glycolysis
  • glycogen
  • protein synthesis
Decreased:
  • glycogenolysis

Term

Glucagon signaling and Metabolic effects of glucagon

 

Glucagon is released from (blank) and travels to two target organs: the (blank) and (blank), where it binds to a cell surface receptor.  There are no glucagon receptors in (blank)

Definition

pancreatic alpha cells

 

liver and adipose

 

muscle

Term

Glucagon signaling and Metabolic effects of glucagon

 

Glucagon receptor is a 7-transmembrane spanning receptor that is coupled to a (blank1); hence the glucagon receptor is a member of the (blank1) coupled receptor family.

 

The (blank1)s that are coupled to GPCRs consist of 3 subunits: (blank), (blank), and (blank)

Definition

G-protein

 

alpha, beta, and gamma

Term

 

 

Glucagon signaling and Metabolic effects of glucagon

 

The alpha subunit (of G protein) binds and is regulated by (blank).

 

(blank2) is the G-alpha subunit that is coupled to the glucagon receptor.

 

In the resting state, (blank2) is bound to (blank1) and exists as an inactive complex with the beta/gamma subunits.  

 

When glucagon binds its receptor, the receptor catalyzes the dissociation of (blank1) from G-alpha subunit and its subsequent binding to (blank).

 

 

Definition

guanine nucleotides

 

G-alpha-s

 

GDP

 

GTP

 

[image]

Term

 

 

Glucagon signaling and Metabolic effects of glucagon

 

The GTP-bound G-alpha-s now dissociates from the beta/gamma subunits and stimulates its effector molecule, an enzyme called (blank).

 

This enzyme catalyzes the conversion of ATP to (blank).  

 

This new form of ATP binds to a protein kinase called (blank), resulting in its activation.

 

This protein kinase phosphorylates a number of metabolic enzymes, thereby altering their activity.  It also phosphorylates a transcription factor called (blank), which regulates expression of metabolic enzyme genes.

 

 

Definition

Adenylate Cyclase

 

cAMP (cyclic AMP)

 

PKA (protein kinase A)

 

CREB - cAMP response element binding protein

 

[image]

Term

Metabolic effects of Glucagon - LIVER

 

Increased: ?? (think opposite of insulin)

 

Decreased: ??

Definition

Increased:

Gluconeogenesis

glycogenolysis

fatty acid oxidation

 

Decreased:

glycolysis

fatty acid synthesis

glycogen synthesis

Term

Metabolic effects of Glucagon - ADIPOSE

 

Increased: ?? 

 

Decreased: ??

Definition

 

Increased: 

TAG hydrolysis (NEED ENERGY!)

 

Decreased: 

N/A

 

Term

 

Metabolic Effects of Glucagon - Muscle

 

 

 

Increased: ?? 

 

Decreased: ??

 

Definition

NO EFFECTS (trick question)

 

THERE ARE NO GLUCAGON RECEPTORS ON MUSCLE MEMBRANES

Term

Other counter-insulin-regulatory Hormones

 

What are two hormones that, like glucagon, also increase when blood glucose decreases?

 

Definition

epinephrine & cortisol

 

[image]

Term

Metabolic effects of Epinephrine - LIVER

 

same as (blank)

Definition

same as glucagon in liver

 

Increased:

Gluconeogenesis

glycogenolysis

fatty acid oxidation

 

Decreased:

glycolysis

fatty acid synthesis

glycogen synthesis

 

 

Term

Metabolic Effects of Epinephrine - ADIPOSE

 

same as (blank)

Definition

same as glucagon

 

Increased:

Gluconeogenesis

glycogenolysis

fatty acid oxidation

 

Decreased:

glycolysis

fatty acid synthesis

glycogen synthesis

Term

Metabolic Effects of Epinephrine - MUSCLE

 

Increases: ??

 

Decreases: ???

Definition

Increases:

Glycogenolysis and

Glycolysis

 

Decreases:  

Glycogen synthesis

Term

Metabolic Effects of Epinephrine - MUSCLE

 

Why would Epinephrine increase both glycogenolysis and glycolysis?

 

role of glycogenolysis is to...

 

glycolysis give energy to ... by ...

 

**but why would Epi decrease glycolysis in liver?

Definition

glycogenolysis = breaks down glycogen --> glucose

 

muscle feeds off glucose

 

uses glycolysis

 

decreases glycolysis in liver since all the glucose from the liver is given primarily to brain and RBCs who need it most!

Term

Metabolic effects of Epinephrine

 

Epi binds to a receptor that is also coupled to (blank)

 

thus, epinephrine also increases (blank) levels, therefore there is an overlap between epinephrine and glucagon action, but 2 important differences exist...

 

  1. ?
  2. ?

 

Definition

G-alpha-s

 

cAMP

 

  1. glucagon does not bind to the Epi receptor and Epi does not bind to the glucagon receptor
  2. there are Epi receptors in muscle and there are similarities and differences in cAMP action in muscle compared to liver

 

Term

Metabolic effects of cortisol

 

Cortisol is a (blank).  It is hydrophobic and a lipid and thus able to pass through (blank).

 

Once inside cells, cortisol (cort) binds to a receptor that is a (blank).

 

the cort/receptor complex will regulate (big blank)

Definition

steroid

 

plasma membrane

 

transcription factor

 

will regulate the transcription of genes encoding metabolic enzymes

Term

Metabolic effects of cortisol - LIVER

 

Increased: ??

 

Decreased: ??

Definition
Only increases gluconeogenesis (make more glucose)
Term

Metabolic effects of cortisol - ADIPOSE

 

Increases: 

 

Decreases:

Definition
Increases TAG hydrolysis only 
Term

Metabolic effects of cortisol - MUSCLE

 

Increases: ??

 

Decreases: ??

Definition

Increases: Proteolysis

 

Decreases: glucose uptake

Term

Metabolic effects of cortisol - Main effect of cortisol??

 

The main effect of cort is to (blank) blood glucose by increasing gluconeogenesis.  

 

The gluconeogenic precursors are mostly (blank)s and (blank).

 

cort deficiency is called (blank) disease

 

in chronic stress, effects of cort cause loss of muscle mass/strength, and re-distribution of fat from sub-cutaneous regions to the abdomen, which increases risk of (blank) disease.

 

the reasons for the unfavorable deposition of fat are not clear, but could result in part from the possibility that the (blank) effect of cort is really "designed" to generate (blank) for gluconeogenesis.  The FFA are not necessarily oxidized, but may be re-deposited in visceral fat.

Definition

increase

 

amino acids and glycerol

 

Addison's disease

 

cardiovascular disease

 

TAG hydrolyzing effect of cort

 

generates glycerol for gluconeogenesis

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