Question

Sulfonylurea is a drug that can bind a human receptor called SUR1. The subsequent signal cascade inhibits ATP-sensitive potassium channels. Please be sure to explain all four questions below in detail.

a) Please describe if this drug will be useful to treat patients with type 1 diabetes mellitus? Please be sure to explain in detail.

b) Will it be useful to treat patients with type 2 diabetes mellitus? Please be sure to explain in detail.

(c) If you do propose its use for either type 1 or type 2 diabetes mellitus, please offer and support a regimen for administering sulfonylurea in the course of a “typical” 24 hour day. Please be sure to explain in detail.

d) One concern about taking sulfonylurea is that it may promote weight gain. Describe a possible mechanism for this. Please be sure to explain in detail.

Answer 1

a) Sulfonylureas bind with SUR1 receptor present in the cell membrane of the pancreatic beta cells. This then inhibit ATP sensitive potassium channels causing depolarization of cell membrane. This depolarization will result in opening up of voltage sensitive calcium channels resulting in influx of calcium ions. The Ca ions bind with insulin granules and increases it's secretion.

b) Type 2 diabetes is caused due to resistance of insulin receptors to insulin hormone. So, sulfonylureas when used along with metformin can be used in the treatment of type 2 diabetes. In type 1 diabetes, there is destruction of beta cells of pancreas. So, this drug cannot be used.

c) Insulin is needed when there is glucose in blood. So, sulfonylureas can be taken immediately after every meal, with dosage adjusted according to the blood glucose levels.

d) Insulin stimulates fatty acid synthesis and deposition of fats in adipose tissue. Sulfonylureas by stimulating insulin secretion causes weight gain.