Insulin Production, Secretion and Action

Question 1

what level are blood glucose levels kept at in normal people?

Answer 1

5mmol

Question 2

what does glucagon do?

Answer 2

increases endogenous glucose levels in the blood

Question 3

what blood glucose level is indicative of diabetes?

Answer 3

> 7mmol

Question 4

most common type of cell present in the pancreatic islets?

Answer 4

beta cells

Question 5

what do beta cells do?

Answer 5

secrete insulin

Question 6

what do alpha cells do?

Answer 6

secrete glucagon

Question 7

what do delta cells do?

Answer 7

secrete somatostatin

Question 8

what do PP cells in the pancreatic islets do?

Answer 8

secrete pancreatic polypeptide

Question 9

what structure in the B cell is insulin’s preprohormone synthesised?

Answer 9

RER

Question 10

what is insulin’s preprohormone called?

Answer 10

preproinsulin

Question 11

what is C peptide?

Answer 11

a by product of preproinsulin’s synthesis into insulin

Question 12

name an ultra short acting insulin preparation?

Answer 12

lispro

Question 13

what is the name given to an insulin preparation that is short acting?

Answer 13

regular

Question 14

name an intermediate acting insulin preparation?

Answer 14

NPH

Question 15

what are the names given to long acting insulin preparations?

Answer 15

lente

ultralente

Question 16

what is the name given to an ultra long acting insulin preparation?

Answer 16

glargine

Question 17

when should insulin lispro be injected?

Answer 17

within 15 minutes of beginning of a meal

Question 18

what should insulin lispro be combined with in T1DM?

Answer 18

a longer acting preparation

Question 19

how can you indicate level of insulin in blood and why?

Answer 19

C peptide as it is in 1:1 ratio with insulin in blood

Question 20

when should you give ultra long acting insulin?

Answer 20

before bedtime

Question 21

when does the body make insulin?

Answer 21

when blood glucose levels are rising

Question 22

how is insulin secreted?

Answer 22

glucose enters beta cells via GLUT 2 transporter
phosphorylated by glucokinase to g6p which initiates glycolysis
ATP made which inhibits potassium ATP channels
get depol which causes voltage Ca channels to open
increased Ca in cell = release of insulin

Question 23

what effect does extremely high blood sugar have on glucokinase?

Answer 23

glucokinases KM only works within normal blood glucose ranges so in diabetes glucokinase can’t work and no insulin can be made

Question 24

when is the only time insulin should be made

Answer 24

when blood glucose levels exceed 5mmol

Question 25

what happens to the beta cells in T1DM?

Answer 25

beta cells are lost

Question 26

what happens to beta cells in T2DM?

Answer 26

unable to sense changes in glucose

Question 27

how many ATP are made per glucose in glycolysis?

Answer 27

36ATP

Question 28

how many phases of insulin release is there?

Answer 28

2

Question 29

why are there 2 phases of insulin release?

Answer 29

5% of insulin is readily available after release | the rest needs to become mobilised for release

Question 30

what do sulfonurea drugs do?

Answer 30

mimic the action of ATP on the sulfonurea receptors of kATP channels (blocking them) to depolarise beta cells

Question 31

what type of diabetes are sulfonurea drugs effective in?

Answer 31

type 2

Question 32

what does diazoxide do?

Answer 32

inhibits insulin secretion by stimulating kATP channels

Question 33

2nd line therapy for T2DM?

Answer 33

sulfonurea drugs

Question 34

who are sulfonurea drugs best for?

Answer 34

those who have trouble injecting insulin or when they have improved glucose control

Question 35

what mutation can lead to neonatal diabetes?

Answer 35

kir6.2

Question 36

what happens when you have a kir 6.2 mutation?

Answer 36

increase in kATP numbers or they are constantly activated

Question 37

what does MODY stand for?

Answer 37

monogenic diabetes of the young

Question 38

what actually is MODY?

Answer 38

monogenic diabetes with genetic defect in beta cell function; usually a form of early type 2

Question 39

most common mutation for MODY?

Answer 39

glucokinase aka MODY 2

Question 40

should MODY patients be treated with insulin or sulfonurea?

Answer 40

sulfonurea

Question 41

what is type 2 diabetes?

Answer 41

initially hyperglycaemia with hyperinsulinaemia so get reduced insulin sensitivity

Question 42

how does insulin get into the cell?

Answer 42

via signal transduction by binding to an insulin receptor

Question 43

what kind of receptor is an insulin receptor?

Answer 43

tyrosine kinase receptor

Question 44

does insulin bind to the alpha or beta subunit first?

Answer 44

alpha

Question 45

what does insulin binding to the alpha subunit cause?

Answer 45

B units will dimerise and phosphorylate themselves

Question 46

what is the correlation between BMI and insulin resistance?

Answer 46

if BMI goes up, insulin resistance goes down

Question 47

what is donohue syndrome?

Answer 47

leprauchanism

Question 48

symptoms of diabetic ketoacidosis

Answer 48

vomiting dehydration increased heart rate distinctive smell on breath

Question 49

where are ketone bodies formed?

Answer 49

liver mitochondria

Question 50

when would a T1DM patient be at risk of DKA?

Answer 50

if insulin supplementation is missed

Question 51

what effect do low levels of insulin do?

Answer 51

inhibit lipolysis | prevent ketone body overload

Question 52

when will acetyl coA be converted into ketones?

Answer 52

limited oxaloacetate supply

Question 53

why do ketone bodies increase when glucose is not available?

Answer 53

fatty acids are oxidised to provide energy and acetyl coA is converted to ketone bodies

Question 54

which quick acting insulin drug is actually quite slow acting?

Answer 54

actrapid

Question 55

how long are long acting drugs SUPPOSED to act?

Answer 55

lantus | levemir

Question 56

how many times should you take long acting insulin?

Answer 56

1 or 2x pd

Question 57

when would you use U500 insulin?

Answer 57

insulin resistant people eg obese

Question 58

what should you look at before starting insulin?

Answer 58

BMI age ability to self manage lifestyle

Question 59

when should you take humulin M3 in relation to meals?

Answer 59

30 mins before

Question 60

when should you take intermediate mixed analogues other than humulin M3 in relation to meals?

Answer 60

same time

Question 61

can site change cause hypos?

Answer 61

yes

Question 62

why do renal problems cause hypo?

Answer 62

body can't clear insulin at the rate they should so insulin stays in the body

Question 63

how can you check for renal function in diabetes?

Answer 63

Us + Es

Question 64

causes of hyperglycaemia?

Answer 64

steroids not enough insulin compliance infection