This lecture covers the mechanisms of action of aldosterone and cortisol through the mineralocorticoid and glucocorticoid receptors, including the formation of receptor-chaperone complexes, nuclear transport, and altered gene transcription. It also explains the specific biological responses to mineralocorticoids and glucocorticoids in target cells, as well as the role of 11B-hydroxysteroid dehydrogenase enzymes in regulating the activation of the mineralocorticoid receptor. The tissue distribution of the mineralocorticoid receptor in the epidermis and hair follicles is also discussed.