The Endocrine Pancreas - Glucagon etc Flashcards
main hormone of fasted state
glucagon
what type of hormone is glucagon
peptide
what hormones elevate blood glucose
glucagon, epinephrine, cortisol and growth hormone
why are amino acids such a potent stimulus for glucagon secretion
because insulin will be released to uptake amino acids, but if its a meal like a steak with lots of protein and not a lot of carbs then insulin will cause hypoglycaemia.
Glucagon is secreted in order to correct this flaw and release more glucose into the blood.
effect of glucagon on glycogenolysis and gluconeogenesis
it increases them
ketone production is increased/decreased by glucagon
increased
what are ketones formed from
fatty acids
glucagon receptors are GPCR or tyrosine kinase
GPCR
system activated by glucagon receptors that phosphorylates liver enzymes to raise BG
adenylatecyclase/cAMP system
inhibition of glucagon secretion
glucose, free fatty acids and ketones, insulin and somatostatin.
essentially signs of high BG
what stimulates release of glucagon in conjunction with insulin
amino acids
what stimuli triggers both insulin and glucagon release
amino acids
stimuli of glucagon release
low BG, high amino acids, sympathetic activity, cortisol and stress
the presence of cortisol will stimulate/inhibit glucagon secretion
stimulate
the presence of somatostatin will stimulate/inhibit glucagon secretion
inhibit
vagus activity stimulates/inhibits glucagon sercetion
stimulates
sympathetic activity stimulates/inhibits glucagon secretion
stimulates
what fasted state hormone can breakdown proteins
cortisol
which fasted state hormones can breakdown fats
epinephrine, cortisol and GH
where is somatostatin secreted
from the hypothalamus and from D cells of pancreas
action of somatostatin
slow down GI tract in various ways
what hormones are suppressed by somatostatin
insulin and glucagon and GH (but only when secreted from hypothalamus)
in what way is somatostatin not an endocrine hormone
it inhibits insulin and glucagon in a paracrine fashion
what would you expect to see in someone with a somatostatin secreting tumour
diabetes like symptoms, as they lose ability to control BG
where is growth hormone secreted from
the anterior pituitary
where is cortisol secreted from
the suprarenal glands
