Glucagon

Question 1

What is the structure of glycogen?

Answer 1

polymer of glucose joined by alpha 1,4 and alpha 1,6 glycosidic linkages

Question 2

How is glycogen synthesised?

Answer 2

condensation:

nucleoside triphosphate, UTP, G1P -> UDP glucose + PPi

Enlongation by glycogen synthase

Branchin enzyme

Question 3

How many serine residues does glycogen synthase have?

Answer 3

3 at C terminus

inactivated by Glycogen synthase kinase 3 (GSK3)

activated by PP1

Question 4

What are orexigenic and anorexigenic neurones?

Answer 4

anorexigenic - release alpha MSH, signals to eat less and metabolise more fuel. Stimulated by leptin and insulin

orexigenic - eat more, metabolise less

Question 5

What is the human telomere structure?

Answer 5

TTAGGG, repeated 2500 times.

division = loss of 50-200bp

Question 6

What are the genes associated with type II diabetes?

Answer 6

Peroxisome proliferator-activated receptor (PPARy)
a2b-adrenergic receptor (binds glucagon)
b2adregenic receptor (binds glucagon)
TNF a
IL6
Insulin like grwoth factor 1
Hepatic lipase
Leptin receptor

Question 7

What are PPARs?

Answer 7

Trnacription factors
Bind to cognate ligand, they form heterodimers with the nuclear receptor RXR

Dimer binds specific regions of DNA called response elements

BASICALLY, regulate adipocytes. causes them to steal lipids from blood

Question 8

What is Metformin?

Answer 8

Type II treatment, also known as glucophage.
Activates AMP activated protein kinase (AMPK). This stimulates glucose uptake into skeletal muscles, inhibit gluconeogenesis in the liver and FA synthesis.

AMPK is also stimulated by exercise

Stops adipose tissue from making FA by inhibiting Acetyle CoA carboxylase

Stimulate FA intake to mitochondria and oxidation

Question 9

How is AMPK regulated?

Answer 9

Activation : Protein phosphatase 2a (PP2a)

Deactivation: AMP activated protein kinase. phosphorylated of a single serine residue

Question 10

What are other treatments for Type II?

Answer 10

Thiazolindinediones - stimulate PPARy

Glibenclamid - stimulate insulin secretion by closing ATP gated pottasium channels in the beta cells

Byetta - incretin mimic, hormones that are released in gastrointestingal tract in response to meals containing glucose. mimics glucagon like peptide 1

Liraglutide