What hormone is typically used in the treatment of severe allergic reactions?

Epinephrine is the hormone commonly used in the treatment of severe allergic reactions, particularly in cases of anaphylaxis. Anaphylaxis is a life-threatening allergic response that can occur rapidly and leads to symptoms such as difficulty breathing, swelling of the throat, and a sudden drop in blood pressure.

Epinephrine works by stimulating the body's alpha and beta adrenergic receptors, which helps to reverse the symptoms of anaphylaxis. It acts quickly to constrict blood vessels, increase heart rate, and dilate bronchial passages, making it crucial for stabilizing patients experiencing an extreme allergic reaction. Typically, it is administered via an auto-injector, allowing for rapid delivery in emergency situations.

The other options listed do not have a role in the treatment of severe allergic reactions: lactase is an enzyme that helps digest lactose, gluten is a protein found in wheat that can cause intolerance in some individuals, and insulin is a hormone crucial for blood glucose regulation but not related to allergic responses. Thus, the prominence of epinephrine in addressing serious allergic reactions is well-established in medical practice, making it the correct choice in this scenario.