Steroid

A steroid is a organic compound, either natural or man-made, which has four cycloalkane rings in its structure. Plants, animals and fungi make hundreds of different natural steroids.^[1]

Steroid hormones are steroids which act as hormones in the body. Natural steroid hormones are usually made from cholesterol in the adrenal glands and gonads. Cholesterol is a plentiful steroid in animal cells: it is important for cell membranes.

Examples of steroid hormones include

• estrogen,
• testosterone,
• progesterone,
• Vitamin D₃ or cholecalciferol.

One review noted: The adrenal gland hormones play a vital role in adapting to "ever-changing environmental and emergency situations, and help vertebrates in their successful survival".^[2]

Prednisone is an important man-made steroid medication, used to treat inflammation.

1. ↑ Lednicer D. 2011. Steroid chemistry at a glance. Hoboken: Wiley. ISBN 978-0-470-66084-3
2. ↑ Reul J.M. et al 1990. Adv. Exp. Med. Biol. 274, 243–256.