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
where are ketone bodies formed?
mitochondria in liver
what does excess acetyle co A convert into?
ketone bodies
what does the accumulation of ketone bodies cause?
acidosis
what exacerbates acidosis?
high glucose excretion -causing dehydration
what is ketoacidosic most associated with/
type 1 diabtes
