Steroid hormone is a steroid that acts as a hormone. Steroid hormones can be grouped into two classes: corticosteroids and sex steroids. Within those two classes are five types according to the receptors to which they bind: glucocorticoids and mineralocorticoids and androgens, estrogens, and progestogens. They are secreted by the adrenal cortex, testes and ovaries, and by the placenta during pregnancy. On the basis of their receptors, steroid hormones have been classified into five groups: glucocorticoids, mineralocorticoids, androgens, oestrogens and progestogens. Steroid hormones help control metabolism, inflammation, immune functions, salt and water balance, development of sexual characteristics, and the ability to withstand illness and injury.