Mechanism of action of sulfonylureas is
?
a) Na ATP channel blocker
b) K ATP channel blocker
c) CI ATP channel blocker
d) Ca ATP channel blocker
Correct Answer - B
Ans. B. K ATP channel blocker
[Ref KDT 7th/e p. 270, 274]
Sulfonylureas provoke a brisk release of insulin from pancreas.
They act on the so called “Sulfonylurea receptors” (SUR1) on
pancreatic (beta-cell membrane - cause depolarization by reducing
conductance of ATP sensitive K. channels.
This enhances influx of Ca’2-- degranulation.
They do not cause hypoglycemia in pancreatectomized animals and
type 1 diabetes (Presence of at least 30% of functional [3-cells in
essential for their action).
A minor action reducing glucagon secretion by increasing insulin and
somatostatin release has been demonstrated.