Steroids - Molecular Structures

There are hundreds of different steroids found in living organisms. Examples of steroids found in humans include estrogen, progesterone, and testosterone. Another common steroid is cholesterol.

Steroids are characterized by having a carbon skeleton with four fused rings. The functional groups attached to the rings distinguish the different molecules. Here's a look at some molecular structures of this important class of chemical compounds.

The two main functions of steroids are as components of cell membranes and as signaling molecules. Steroids are found throughout the animal, plant, and fungi kingdoms.

Aldosterone

Aldosterone is a steroid hormone.
Aldosterone is a steroid hormone. In humans, its function is to cause the kidney tubules to retain sodium and water. Ben Mills

 

Cholesterol

Cholesterol is a lipid that is found in the cell membranes of all animal cells.
Cholesterol is a lipid that is found in the cell membranes of all animal cells. It also is a sterol, which is a steroid characterized by an alcohol group. Sbrools, wikipedia.org

Cortisol

Cortisol
Cortisol is a corticosteroid hormone produced by the adrenal gland. It sometimes is referred to as the "stress hormone" as it is produced in response to stress. Calvero, wikipedia commons

Estradiol

Estradiol is one form of the class of steroid hormones known as estrogens.
Estradiol is one form of the class of steroid hormones known as estrogens. Anne Helmenstine

Estriol

Estriol is one form of estrogen.
Estriol is one form of estrogen. Anne Helmenstine

Estrone

Estrone is one form of estrogen.
Estrone is one form of estrogen. This steroid hormone is characterized by having a ketone (=O) group attached to the D ring. Anne Helmenstine

Progesterone

Progesterone is a steroid hormone.
Progesterone is a steroid hormone. Benjah-bmm27, wikipedia.org

Progesterone

Progesterone belongs to a class of steroid hormones called progestogens.
Progesterone belongs to a class of steroid hormones called progestogens. In humans, it is involved in the female menstrual cycle, embryogenesis, and pregnancy. Anne Helmenstine

Progesterone is a female sex hormone involved in pregnancy, embryogenesis, and the menstrual cycle.

Testosterone

Testosterone is one of the steroid hormones.
Testosterone is one of the steroid hormones. Anne Helmenstine

Testosterone is an anabolic steroid. It is the principal male sex hormone.