Flashcards in Insulin secretion and signalling Deck (42)
which cells does insulin come from
pancreatic B cells
where about in the pancreas is insulin secreting cells located?
what does alpha cells secrete
what cells produce somatostatin
what do PP cells secrete?
where is insulin peptide synthesised?
in the rough endoplasmic reticulum of pancreatic b cells
is an insulin chain single or poly?
what links two polypeptide chains together in a polypeptide insulin chain ?
What transporter does glucose enter b cells through?
what phosphorylates glucose?
true or false, increased glucose increases intracellular ATP concentration
true or false, ATP promotes ATP sensitive K+ channels
FALSE- ATP inhibits the K channels
what does inhibition of the K ATP channels lead to?
depolarisation of the cell membrane
what does depolarisation of the cell membrane lead to?
Ca2+ channel opening
What does an increased Ca2+ cause?
fusion of the secretory vesicles and cell membrane to release insulin
is release of insulin biphasic or monophasic
BIPHASIC you turd
what are the two proteins that make up K ATP channels?
SUR1 and Kir6.1
why are the two proteins required in the K channels?
provide a functional channel
What is K ATP channels regulated by?
sulphonylurea and ATP- inhibts channels to promote depolarisation. DIAZOXIDE stimulates K ATP channels thus inhibits insulin secretion.
what is MODY?
maturity onset diabetes of the young- early onset type 2 diabetes- defect in insulin secretion.
How does MODY happen?
genetic defect in B cell function.
What is impaired in mody? (used for phosphorylation)
What is primarily used to treat MODY
what does genetic screening help you distinguish
type 1 and MODY- type 1= insulin, MODY= sulphonyurea
What is typ 1 diabetes
loss of insulin secreting B cells
what is type 2 diabetes
defect in insulin sensitivity, hyperglycaemia
what is MODY
defect in glucose sensitivity in pancreas/ loss of insulin secretion
What is the insulin receptor that insulin binds to?
DIMERIC tyrosine kinase (2 alpha- extracellular and 2 beta cytoplasmic)
by proteins phosphorylating on any hydroxyl group this gives...
a negative charge into protein structure