Lecture 3 Flashcards
When is glucagon released and from where?
released when blood glucose is low
- from alpha cells in the islets of Langerhans in the pancreas
Where is glucagon released to?
liver cells glucagon receptors
What does glucagon inactivate; what happens; via protein kinase A?
phosphofructokinase 2
- suppresses glycolysis
what does glucagon activate; what happens; via protein kinase A
fructose bisphosphatase 2
- stimulates gluconeogenesis
What does Protein kinase A do?
phosphorylate proteins eg. such as those in glucagon and epinephrine schemes to activate them
What does epinephrine do?
raises blood glucose levels
- dialates blood vessels
what does glucagon do?
maintains homeostasis
where is epinephrine released from?
adrenal glands
to the muscle cells and adipose tissues
What does epinephrine activate via protein kinase A
phosphorylase kinase
What does epinephrine inactivate via protein kinase A
glycogen synthase
What is the overall effect of epinephrine in the body
glucose degredation
why are there so many steps in these signalling systems?
to enable tight control of hormonal actions
what are the common components of the two hormone mediated events
- both involve a stimulatory G protein
- both involve increase in the secondary messenger cAMP
- both involve activation of protein kinase A
different components of these two hormone mediated events?
protein kinase A phosphorylates different targets
What drug is commonly used to trigger cAMP production today?
Byetta
