Question

Insulin secretion is inhibited by:

• A. Secretin
• B. Epinephrine
• C. Growth hormone
• D. Gastrin

Hint:

Stress hormones acting on alpha-2 receptors switch insulin off.

Answer 1

The Correct Option is B

To find the inhibitor of insulin release, picture the pancreatic beta cell and what each listed agent does to it.

Epinephrine is the clear suppressor. By engaging alpha-2 adrenergic receptors on the beta cell, it cuts intracellular cyclic AMP and shuts down insulin output. This fits the logic of the stress response: when adrenaline surges, the body wants glucose available in the blood for muscle and brain, so storing it away with insulin would be counterproductive.

The rest of the list pushes insulin the other way. The gut hormones secretin and gastrin both nudge the beta cell to release more insulin in the fed state, sharing in the incretin-type response that prepares the body for an incoming glucose load. Growth hormone is a more subtle case: it opposes insulin action in tissues and is diabetogenic, yet it stimulates insulin secretion and tends to drive insulin levels up rather than down.

That leaves epinephrine as the single agent that inhibits insulin secretion, via its alpha-2 effect on the beta cell.

\[\boxed{\text{Epinephrine}}\]