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Metabolism > 3.1-Insulin,Glucagon, & Epi > Flashcards

3.1-Insulin,Glucagon, & Epi Flashcards

1
Q

Where is Epinephrine made?

A

The Adrenal Medulla!

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2
Q

Where are both Insulin and Glucagon made?

A

The Pancreas!

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3
Q

Generally are the effects of insulin more anabolic or catabolic?

A

Insulin is generally more anabolic (Build fat, build glycogen)

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4
Q

Are the effects of Glucagon/Epinephrine generally anabolic or catabolic?

A

Glucagon and Epi are typically more Catabolic (break down fat for energy, break down glycogen for energy, (make ketones in case of emergency)

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5
Q

What is the R.L.S. of the synthesis of Epinephrine? What enzyme is used?

A

Tyrosine—>Dopa Enzyme: TYROSINE HYDROX-YLASE

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6
Q

What hormone stimulates the intermediates that synthesize Epinephrine?

A

ACTH (AdrenoCorticoTropicHormone) stimulates both Tyrosine Hydroxylase AND Dopamine-Beta-hydroxylase

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7
Q

What type of cell secretes Epi? Not sure how important it is…

A

Chrom-affinCells

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8
Q

Its time to finaly learn a freaking G Protein pathway. Describe the Epi G Protein pathway… 5 Steps

A
  1. Epi binds to the receptor 2. Gamma/Beta Subunit moves and the GDP on the Alpha Sub unit is phosphorylated to GTP 3.The alpha sub unit binds to Adenylate Cyclase 4. AC stimulates the formation of cAMP 5. cAMP activates Protein Kinase A
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9
Q

What are the three main conceptual effects of Epi on: Insulin, LipoLysis, and Glucagon? WHERE are these happening?

A

INHIBITS Insulin Release in PANCREAS….STIMULATES lipolysis in ADIPOSE tissue…..STIMULATES Glucagon release in PANCREAS

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10
Q

What is the overall message that Epi sends out? What does it do to HR? BP? Respiratory Passages?

A

Let’s get busy! Increase HR, Increase BP, Increase Dilation of Respiratory pathways (EPI PEN)

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11
Q

What are the metabolic effects that Epi has? Glycogen Breakdown?Glycogen Synthesis?GNG (Liver)?Glycolysis (muscle)?

A

Increase Glycogen Breakdown, Decrease Glycogen Synthesis, Increase GNG (in Liver), Increase Glycolysis (in Muscle)

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12
Q

What are the three hormones we discussed from Islets of Langerhans? What cell type? What are the %s for each cell type?

A

Insulin from BETA cells 80% of Islet cells……Glucagon from ALPHA cells 15% of islets….Somatostatin(GHIH) from DELTA cells 5% of islets

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13
Q

Are the islet of langerhans cells and their hormones endocrine, paracrine or both?

A

BOTH Endocrine and Peracrine fxns

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14
Q

How many AAs are in Glucagon?

A

29 AA sequence

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15
Q

What are the 4 pathways that Glucagon increases? Can you teach this to someone else?

A

Glucagon increases 1.BLOOD GLUCOSE, 2.GNG, 3.GLYCOGENOLYSIS, and 4.LIPOLYSIS

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16
Q

What does Glucagon do in hypoglycemic diabetics?

A

Reverses insulin induced hypoglycemia. Been grown in bacteria since ‘98 yo.

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17
Q

What type of signal cascade does Glucagon start?

A

Same as Epi! G-Protein–>Adenylate Cyclase–>cAMP–>PKA

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18
Q

What organ/cells does glucagon typically target?

A

Hepatocytes

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19
Q

What is the effect of glucagon on glucose metabolism?

A

1 GET GLUCOSE into BLOOD! So, Amino acids, Glycerol, Oxaloacetate—>glucose..

20
Q

READY for some target enzyme analysis?! BIG concepts so take your time…What does glucagon so to Glycogen Phosphorylase?

A

Increases Glycogen Phosphorylase (Breaks down glycogen to glucose)

21
Q

What does glucagon do to glycogen synthase?

A

Decreases glycogen synthase (“Stop making glycogen!”-Glucagon)

22
Q

What does glucagon do to Phosphofructokinase-1?

A

Decreases Phosphofructokinase-1 activity (“Stop doing glycolysis!”-glucagon)

23
Q

What does glucagon do to Fructose-1,6-Bisphosphate?

A

Increases F-1,6-BP activity (“Reverse glycolysis”-glucagon)

24
Q

What does glucagon do to Pyruvate kinase?

A

Decreases Pyruvate kinase activity (“Stop the last step in glycolysis”-glucagon)

25
Q

What does glucagon do to triacylglycerol lipase?

A

Increases triacylglycerol lipase aka. hormone induced lipase (“break down fat for energy”-glucagon

26
Q

What is the product of ProGlucagon that augments the resease of insulin in the blood? CRAZY concept, I know. But, what is the name of the peptide and what is its “nickname”?

A

It is Glucagon Like Peptide-1 (GLP-1). It is considered a “incretin”. (“increase-in”)

27
Q

What are the two main functions of GLP-1?

A
  1. To increase insulin. Its like an “insurance policy” to really help get sugar out of the blood 2. Like CCK, it sends a satiety signal to the brain.
28
Q

Where is GLP-1 made as opposed to glucagon?

A

GLP-1 is made in the intestinal “L cells”, where as glucagon is made in pancreatic alpha cells.

29
Q

Do both insulin and glucagon start as “preprohormones”? Where might modifications happen?

A

yes. translated in cytoplasm/ER. modified in Golgi released from a transport vesicle

30
Q

What is the half life of insulin? What is the half life of its patnah c-peptide?

A

Insulin ~5 minutos, C pep ~30min. Doc will more likely measure C pep for accuracy when checking insulin levels

31
Q

What are the 3 steps of post-translational modification of insulin?

A
  1. PreProInsulin w signal sequence 2. ProInsulin (lost signal seq, gained DiSulfide bridges (in ER) 3. In golgi, break down to Insulin and c-peptide.
32
Q

What are the 4 main structural features of insulin?

A
  1. Alpha Chain (21AA) 2. Alpha chain “intrachain” disulfide bond 3. Beta Chain(30AA) 4.disulfide bridges in the middle of alpha and beta
33
Q

How many units of insulin are packaged together for secretion? What metal stabilizes them?

A

6 (hexamer) stabilized by Zinc

34
Q

How is insulin released from the beta cell? if you get this wrong, death! WHEN does it occur?

A

exocytosis, High [blood sugar]!

35
Q

Is insulin’s signal transduced via a G Protein pathway?

A

NOPE

36
Q

What is the molecule attached to an AA thatWHEN PHOSPHORYLATED starts biological effects on the target cell for Insulin?

A

Molecue: IRS-Tyrosine-P

37
Q

What are the two main effects of insulin signaling a cell that we discussed in class?

A

Common theme of Insulin Building things… 1. Mitogenesis (cell proliferation) 2. Glucose Transport: Tells cells to present GLUT4’s to bring in glucose!!

38
Q

What are the two most important molecules for “sensing” blood glucose?

A

GLUT-2 & GlucoKinase (Getting glucose in, and trapping it)

39
Q

What is the first step after a pancreatic beta cell has sensed high glucose levels in the blood? What tipped it off?

A

Because of HIGH [ATP] from lots of new glycolysis, K+ channels CLOSE

40
Q

What does closing a K+ channel do to the cell polarity?

A

Trapping more + ions in so it will depolarize and make the inside of the cell +

41
Q

What does the K+ channel closing do after it has depolarized a pancreatic beta cell?

A

Voltage gated Calcium channels open and Ca2+ RUSHES in! This stimulates insulin secretion!

42
Q

After a Carb rich meal, what do insulin levels do? What do glucagon levels do?

A

Insulin levels rise, glucagon levels fall

43
Q

After a high protein meal, what do insulin levels do? What do glucagon levels do?

A

they BOTH increase!

44
Q

What are the three amino acids that stimulate the release of insulin? How do each of them operate?

A

ALANINE and GLYCINE share a Na+ symport. The influx of Na+ depolarizes the cell. ARGININE directly polarizes the cell because it is a CATION! (A very positive PIRATE)

45
Q

How did they discover incratins? Hint: Why did we have a gila monster in our ppt?!

A

Gila Monsters have incretins in their saliva. Scientists have isolated it and put it into type II diabetics medication to stimulate insulin release

Metabolism (35 decks)

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