Endocrine pancreas

Question 1

Cells pancreas

Answer 1

A - glucagon
B - insulin - centre of islet
D - somatostatin
F - polypeptide

Question 2

Insulin formation

Answer 2

polypeptide with disulphide bridges
made in rER and packaged in golgi
prepro
folded with disulphide bridges
proinsulin
c peptide detaches
insulin - then enters golgi and packaged into membrane bound granules
(c peptide measure of endogenous insulin production)

Question 3

Insulin effects

Answer 3

seconds - K, glucose and AAs go intracelllar
Minutes - inhibits protein degradation, and gluconeogenic enzymes, activates protein synthesis and glycogen synthesis and glycolytic enzymes
hours - increases mRNA for lipogenic enzymes

Question 4

Glucose transport

Answer 4

cells - fascilitated diffusion GLUT 1-7
intestines - secondary actie transport with Na (SGLT 1+2)

n.b. glut 4 mobilised to cell membranes by excercise - independent of insulin

Question 5

Glucose receptor

Answer 5

extra cellular alpha
intracellular beta
TK domain activated

Question 6

Glucose tolerance

Answer 6

decreased glut 4 expression
same glucose from GIT
same output from liver as no negative feedback

Question 7

Normal glucose where it goes

Answer 7

50% CO2 and H2O
5% glycogen
40% fat

diabetes same glycogen, reduced everything else

Question 8

hypoglycaemia –>

Answer 8

inhibits insulin secretion
glycogenolysis due to glucagon and adr
decreased peripheral use glucose due to growth hormone and cortisol (negligible)

Question 9

Regulation insulin secretion

Answer 9

40 units/ day
glucose to b cell via glut2
broken to pyruvate via glucokinase
pyrvate to citric acid in mitochondria
oxidative phosphorylation
ATP reduces K efflux
B cell depolorised and exocytosis insulin

Question 10

Sulphonylurea

Answer 10

blocks K channels B cells
therefore more depolarised and insulin release
e.g. gliclazide
SE hypoglycaemia

Question 11

Biguanides

Answer 11

decrease gluconeogenesis in liver
SE lactic acidosis
e.g. metformin

Question 12

Thiazolidinediones

Answer 12

increase peripheral glucose disposal (insulin mediated)
reduce insulin resistance
e.g. pioglitazone

Question 13

cAMP

Answer 13

increased -> increased insulin
e.g. beta agonists and glucagon and throphyline
beta increases insulin, alpha decreases, overal decrease

Question 14

Mechanism glucagon

Answer 14

in liver acts on GPCRs
adenyl cyclase -> cAMP -> pKA -> phophrylase -> glycogenolysis
also works via phospholipase C activation

Question 15

Glucagon causes release of

Answer 15

GH and somatostatin release (an insulin)

Question 16

Glucagon inhibition

Answer 16

Glucose -> insulin -> GABA -> A cell Cl influx and inhibition
Alpha adrenergic
secretin
Somatostatin
FFAs and ketones

Question 17

Glucagon excitation

Answer 17

Beta
AAs
cortisol
theophylin
ACh
hypoglycaemia

Question 18

Somatostatin

Answer 18

Growth hormone inhibiting hormone
14 and 28 (more potent)
inhibits insulin, glucagon and pancreatic polypeptide
somatostatinoma - hyperglycaemia, dyspepsia, slow gastric amptying an gallstones

Question 19

Pancreatic polypeptide

Answer 19

stimulated by excercise and fasting
inhibited by cholinergic, somatostain and glucose
F cells
Under cholinergic control
Inhibits gastric emptying and biliary secretion and CCK

Question 20

Stimulation insulin release

Answer 20

GIP
AAs
Glucose
Acetylcholine
Sulfonylureas
CCK