Glucocorticoid receptors are intracellular proteins to which drugs of the glucocorticoid class bind and cause physiologic affects. They are related to mineralocorticoid receptors and less so to androgen receptors and estrogen receptors.
Glucocorticoids were named for their actions on blood glucose concentration, but they have equally important effects on protein and fat metabolism. Cortisol is the most important natural example.[1] A wide range of synthetic drugs are in this category, and have a wide range of beneficial and side effects.[2]