DRUGS AND THEIR TARGETS IN T2DM - JP Flashcards
Describe the steps in insulin secretion
- Increase in Blood Glucose
- Glucose enters pancreatic beta cells via GLUT-2 transporter.
- Glucose gets phosphorylated to Glucose-6-Kinase by Glucokinase
- Glycolysis of Gluco-6-Kinase yields ATP.
- Katp channels close causing membrane DEPOLARISATION.
- Depolarisation causes Ca2+ channels to open and Ca2+ to enter the cell triggering insulin secretion.
What are the 8 subunits of the Katp channel?
4 Potassium Inward Rectifier 6.2 Subunits (Kir6.2)
4 Sulphonylurea Receptor 1 Subunits (SUR1)
ATP binds to what part of the Potassium channel causing closure?
Kir6.2
What binds to SUR1 subunits to keep the channel open, maintaining the membrane potential?
ADP-Mg2+
What do Sulphonylureas bind to?
SUR1
Displacing ADP-Mg2+ and closing the Katp channel.
Causes depolarisation and insulin release
Name a Sulphonylurea?
Tolbutamide, Gliclazide and Glipizide
Why are Sulphonylureas known as ‘insulin secretagogues’?
They cause pancreatic beta cells to release insulin
Name some downsides of Sulphonylureas?
Weight gain
Hypoglycaemia (excessive insulin secretion)
What are Glinides?
Drugs that work similar to Sulphonylureas but don’t cause hypo’s
Name two incretins
GLP-1 (Glucagon Peptide Like-1)
GIP (Glucose Dependent Insulinotropic Peptide)
Where are incretins released from?
Enteroendocrine cells in the small intestine
How do incretins lower blood glucose?
Enhance insulin release from pancreatic beta cells (enhanced uptake of glucose)
Decreases glucagon release from pancreatic alpha cells (reduced production of glucose)
What does DPP-4 do?
Terminates the action of incretins (GLP-1 and GIP)
How do ‘Gliptins’ work
Inhibit the action of DDP-4, prolonging the action of GLP-1 and GIP
What do all DPP-4 names have in common?
All have gliptin in the name
I.e saxagliptin, vildagliptin, linagliptin and alogliptin.