Pancreatic Hormone Physioloy

Question 1

Which hormones do Alpha pancreatic cells release?

Answer 1

Glucagon

Proglucagon

Question 2

Which hormones do Beta pancreatic cells release?

Answer 2

Insulin
C-peptide
Proinsulin 
Islet amyloid polypeptide
GABA

Question 3

Which hormones do Delta pancreatic cells release?

Answer 3

Somatostatin

Question 4

Which hormones do Epsilon pancreatic cells release?

Answer 4

Ghrelin

Question 5

Which hormones do F or PP pancreatic cells release?

Answer 5

Pancreatic polypeptide.

Question 6

What are the steps in insulin secretion/creation?

Answer 6

Insulin gene translated into preproinsilin in ER where it will be cleaved into proinsulin.

Proinsilin is packaged into secretory vesicles with C-peptide.

A mature insulin vesicle contains 2 peptides linked by disulfied bonds in vessel with C-peptide in a 1:1 ration.

Question 7

Why can C-peptide be used as an insulin creation measurement?

Answer 7

C-peptide is created in a 1:1 ratio with insulin.

Question 8

What neural input stimulates insulin release?

Answer 8

Vagal stimulation via acetylcholine acting on M3 receptors bound to Gq activating PLC to increase intracellular calcium.

Question 9

What hormonal input stimulates insulin release?

Answer 9

Glucagon-like peptide (GLP1) stimulates insulin secretion !

Catecholamines also act to stimulate insulin release via epinephrine surges.

Question 10

How does epinephrine relate to isnulin?

Answer 10

Epinephrine binds Beta adernergic receptors leading to an increase in insulin surge.

Question 11

How does Glucose stimulate insulin release?

Answer 11

Glucose in the most potent stimulator of release within the pancreatic Beta cells and does so by increasing intracellular ATP and depolarizing the membrane through the potassium channel and calcium influx.

Question 12

How is insulin release inhibited?

Answer 12

Norepinephrine via sympathetic response binds alpha adernergic receptors leading to inhibition of insulin release.
Somatostatin released with insulin also causes inhibition of its release.

Question 13

How does Glucose act on B- islet pancreatic cells

Answer 13

Increases ATP and inhibits potassium channels leading to a membrane depolarization effecting the calcium channels and allowing insulin release.

Question 14

How do parasympathetics effect insulin release?

Answer 14

Parasympathetic activation of M3 receptors leads to insulin release.

Question 15

What effect does insulin have on the liver?

Answer 15

promotes anabolism i.e. 
glycogen synthesis and storage
Inhibits glycogen breakdown
Increases protein synthesis
Increases triglyceride synthesis.

Inhibits Catabolism i.e.
inhibits glycogenolyisis
Inhibits ketogenesis
Inhibits gluconeogenesis

Question 16

What effect does insulin have on muscle?

Answer 16

Promotes protein synthesis (AA uptake)

Increases glycogen synthesis with GLUT4 glucose utake.

Question 17

How does insulin act on Fat cells?

Answer 17

Increases triglyceride storage through
promoting free fatty acid uptake
Promoting esterification of free fatty acids
Inhibiting lipolysis

Question 18

How does somatostatin effect insulin and glucagon?

Answer 18

Somatostatin inhibits both insulin and glucagon release

Question 19

What two metabolic processes does glucagon mainly promote?

Answer 19

Glycogenolysis
Ketogenesis (epinephrine and cortisol do this as well)

Question 20

What two processes does insulin mainly promote?

Answer 20

Gluconeogenesis
Glycogenesis
Glycolysis.

Question 21

What does IAPP do and where is it produced?

Answer 21

Produced by the beta cells with insuin and is a negative regulator of glucagon and inhibits GI motility also upregulating appetite.

Question 22

What does pancreatic polypeptide do and where is it produced?

Answer 22

Secreted by F cells or PP cells and regulated by the vagus nerve.
This provides exocrine effects of the pancrease, gallbladder contraction, gastric acid secretion and GI motitilty.

Think rest and digest!

Question 23

What does Somatostatin do and where is it released?

Answer 23

Released from Delta cells regulating insulin release.

Regulates through activation os SSTR-5 somatostatin receptor inhibiting insulin release in a paracrine fashion.

Question 24

What does Ghrelin do and where is it made?

Answer 24

Composed in the Epsilon cells promoting gastric emptying and stimulating apetite.

Question 25

What does GLP1 do and where is it created?

Answer 25

Promotes both insulin and somatostatin release promoting growth of Beta cells.
Helps to treat diabetes!

Question 26

What target enzyme breaks down GLP1?

Answer 26

Dipeptidyl peptidase 4 (DPP-4)