Biochemistry Flashcards
Which cells secrete insulin?
Beta cells
What do alpha cells secrete?
Glucagon
What secretes somatostatin
gamma cells
what do PP cells secrete
pancreatic polypeptide
Where is insulin synthesized`
rough ER of pancreatic beta cells
Describe the synthesis of insulin
Synthesized as a larger single chain preprehormone called preproinsulin.
Cleaved to form insulin.
Describe the structure of insulin.
Two polypeptide chains linked by disulphide bonds.
Name the by product of cleavage in insulin production
C peptide
How does glucose enter the beta cells
GLUT 2 glucose transporters
What happens to glucose once inside the cell
it is phorphorylated
what is the name of the enxyme that phorsphorylates glucose in beta cells
glucokinase
What two proteins do Katp channels consist of
An inward rectifier subunit (Kir6.1).
A sulphonylurea receptor (SUR1).
What class of drugs inhibit Katp?
sulphonylurea eg. tolbutamide or glibenclamide
Name a drug that stimulates Katp and therefore inhibits insulin secretion
Diazoxide
