Insulin Secretion and Signalling Flashcards
what cells secrete insulin?
B cells (beta)
what cells secrete glucagon?
alpha cells
what cells secrete somatostatin?
sigma cells
what cells secrete pancreatic polypeptide?
PP cells
where is insulin made?
in RER of pancreatic B cells
how does glucose enter B cells?
via GLUT2 glucose transporter
increased metabolism of glucose leads to an increase in what?
intracellular ATP
what does ATP inhibit?
the ATP sensitive K+ channels which leads to depolarization of the cell membrane
what does depolarization of the cell membrane allow?
the opening of voltage gated Ca++ channels
what does an increase in intracellular Ca++ cause?
release of insulin
how many proteins make up Katp channels?
2
what type of drug directly inhibits Katp channels?
sulphonylurea
what is the difference between type 1, type 1 and MODY?
type1- loss of insulin secreting B cells
type 2- reduced insulin sensitivity in tissues
MODY- defective glucose sensing in pancreas and or loss of insulin secretion
what does insulin bind to?
insulin receptor
which part of the receptor does insulin bind to?
alpha units
