Steroid Hormones
Steroid hormones are hormones that are derived from cholesterol. They are unusual in that they are not stored for release after synthesis. Therefore, the level of a circulating steroid hormones is controlled primarily by its rate of synthesis, which is often controlled ultimately by signals from the brain. These signals usually act through intermediary hormones.
The five major classes of steroid hormones are the progestins, mineralocorticoids, glucocortiocoids, androgens, and estrogens (Figure 19.24)