L76: Pancreas

Question 1

What’s the ““islets of langerhans”

Answer 1

Endocrine pancreas - 3 major cell types. Minority of pancreatic mass.

Question 2

Exocrine pancreas

Answer 2

Majority of cells. Digestive enzymes and secretions.

Question 3

What do epsilon cells secrete?

Answer 3

Ghrelin

Question 4

What do delta cells secrete?

Answer 4

Somatostatin

Question 5

What do beta cells secrete?

Answer 5

Insulin

Question 6

What do PP cells secrete?

Answer 6

Pancreatic polypeptide

Question 7

What does pancreatic polypeptide do?

Answer 7

inhibits acinar cells via paracrine action

Question 8

What is amylin?

Answer 8

Synergizes with insulin. Can create plaques if built up in stressed out B-cells

Question 9

C-peptide half life?

Answer 9

35 min. Good indicator of pancreatic function.

Question 10

Good indicator of pancreatic function

Answer 10

C-peptide

Question 11

Why is cleavage of C-peptide critical?

Answer 11

exposes end of insulin chain that interacts with receptor

Question 12

What glucose transporter is on the Beta-cell?

Answer 12

Glut2

Question 13

What is the “glucose sensor” of the beta-cell?

Answer 13

Glucokinase

Question 14

What senses ATP from glucose metabolism in B-cell, promoting closure of K+ channels?

Answer 14

SUR subunit

Question 15

What kind of drugs act on SUR to close the K+ channel, and promote insulin release?

Answer 15

Sulfonylurea drugs

Question 16

What promotes vesicle (of insulin) release at B-cell?

Answer 16

Ca++ influx

Question 17

What inhibits insulin release at B-cell?

Answer 17

ACh

Question 18

What potentiates insulin release at B-cell?

Answer 18

FFA/aa’s (increase ATP through oxidation), and GLP1 (Incretin)

Question 19

Describe the nature of insulin release

Answer 19

biphasic

Question 20

Insulin binds what type of receptor?

Answer 20

Tyrosine kinase

Question 21

Which GLUT is insulin dependent

Answer 21

GLUT4

Question 22

What two pathways does the insulin receptor promote

Answer 22

1. Increase GLUT4 installation

2. Increase growth/mitogenetic actions

Question 23

What 4 factors does pro-glucagon consist of?

Answer 23

GRPP, glucagon, GLP-1, GLP-2

Question 24

What happen to GRPP-Glucagon in the pancreatic islet cell?

Answer 24

Cleaved to GRPP + glucagon (Active peptides)

Question 25

T/F: glucagon phosphorylates the bifunctional enzyme

Answer 25

True, it phosphorylates the enzyme, conferring PHOSPHATASE activity. Dephosphorylation of downstream enzymes promotes gluconeogenesis.

Question 26

T/F: insulin dephosphorylates the bifunctional enzyme

Answer 26

T: insulin dephosphorylates the bifunctional enzyme, conferring KINASE activity. Phosphorylation of the downstream enzymes promotes glycolysis

Question 27

What inhibits hepatic ketogenesis

Answer 27

insulin

Question 28

Can insulin inhibit glucagon secretion at the alpha-cell?

Answer 28

Yes

Question 29

Can glucagon inhibit insulin secretion at the b-cell?

Answer 29

no

Question 30

What promotes hepatic ketogenesis?

Answer 30

Catecholamines, glucagon

Question 31

SS14 (delta cells)

Answer 31

suppresses insulin release

Question 32

Synergistic with insulin regulation of blood glucose

Answer 32

amylin

Question 33

Contributes to amyloid formation in beta-cell

Answer 33

amylin

Question 34

Inverse correlation with ghrelin and

Answer 34

obesity

Question 35

What two hormones have a permissive effect on gluconeogenesis and lipolysis?

Answer 35

GH and cortisol

Question 36

Ghrelin has what effect on hypothalamus?

Answer 36

Promotes appetite

Question 37

What happens if GH is present, but not insulin?

Answer 37

“in the absence of insulin, GH is elevated but cannot stimulate hepatic IGF-1. Result: direct glucose mobilization effects of GH, but no cellular proliferation effects of IGF-1. Also, no negative feedback to GH.”