Which of the following is a product of mast cell degranulation?

Mast cell degranulation is a crucial event in the immune response, particularly in allergic reactions and asthma. During this process, mast cells release various mediators into the surrounding tissue. Histamine is one of the primary substances released during mast cell degranulation. It is responsible for several physiological effects, such as vasodilation, increased vascular permeability, and bronchoconstriction. These effects contribute to typical allergy symptoms, such as itching, swelling, and difficulty breathing.

The other substances listed—cholesterol, cortisol, and prostaglandin—are not directly released as a result of mast cell degranulation in the same manner. Cholesterol is a structural component of cell membranes and a precursor for steroid hormones but is not a mediator of mast cell activation. Cortisol, a steroid hormone produced by the adrenal glands, is involved in regulating various body functions, including the immune response, but is not released by mast cells. Prostaglandins, while also involved in inflammatory processes and can be produced by various cells including mast cells, are not the primary mediator released during mast cell degranulation. Instead, histamine is the key product typically associated with this specific process.