Pancreas

Question 1

Beta cells

Answer 1

73-75%

Synthesize and secrete insulin

Question 2

Alpha cells

Answer 2

18-20%

Synthesize and secrete glucagon

Question 3

Delta cells

Answer 3

4-6% synthesize and secrete somatostatin (SS14)

Question 4

PP

Answer 4

Less than 1%

Secrete pancreatic polypeptide. Inhibit acinar cells via paracrine action

Question 5

Epsilon cells

Answer 5

Less than 1%

Synthesize ghrelin

Question 6

GLUT 1

Answer 6

Expression: Brain vasculature, erythrocytes, skeletal muscle, fat, heart (minor role)

Function: Insulin-independent, uptake under basal conditions

Question 7

GLUT 2

Answer 7

Expression: Pancreatic beta cells, liver, intestine, kidney

Function: Insulin-independent, low affinity, uptake when glucose levels are high

Question 8

GLUT 3

Answer 8

Expression: neurons

Function: Insulin-independent, major transporter in brain

Question 9

GLUT 4

Answer 9

Expression: Skeletal muscle, fat, stored inside cell under basal conditions

Function: Insulin-dependent!

Question 10

GLUT 5

Answer 10

Expression: spermatozoa, small intestine

Function: fructose transporter

Question 11

Somatostatin (SS14)

Answer 11

Produced by delta cells
Stimulated by high fat, high carb meals
Inhibited by insulin
Suppresses insulin release- used in clinic for management of insulin-suppressing tumors

Question 12

Amylin

Answer 12

Released with insulin from vesicles in beta cells
Synergistic with insulin in regulation of blood glucose
Circulating amylin increased in obesity, hypertension
Possibly contributes to beta cell destruction by forming amyloid

Question 13

Ghrelin

Answer 13

Most circulating ghrelin produced in the stomach;
Stimulates food intake at hypothalamus
Stimulates GH release
Inverse correlation between circulating ghrelin and obesity

Paracrine action on beta cells;
Inhibits insulin release via G activation; opens K channels
Decreases intracellular Ca, decreases insulin release

Question 14

GH and Cortisol

Answer 14

Antagonize insulin
Permissive effects on gluconeogenesis and lipolysis

Delayed response (6 hours) - defense against prolonged hypoglycemia (starvation)

Question 15

Catecholamines (epinephrine)

Answer 15

Like glucagon, raise plasma glucose levels
Increased during stress and exercise
Inhibits insulin release directly at beta cell, stimulated glucagon in alpha cell
Increases hepatic glucose output
Decreases glucose uptake in skeletal muscle/adipose tissue