What Are Steroid Hormones?

Steroid hormones are lipid molecules that act as hormones by causing chemical changes in other body cells. There are many types of naturally occurring steroid hormones and these are essential for proper body functioning. There are also a number of synthetic steroid hormones, known as anabolic steroids. Anabolic steroid hormones can severely disrupt the body's normal hormonal balance, resulting in a variety of health problems.

Definition

• A steroid hormone is a lipid--an organic (carbon containing) molecule that is fat soluble but not water soluble--that also acts a hormone. All steroid hormones are made up of three six-carbon rings, one five-carbon ring, and a unique side chain, a basic structure that is characteristic of the cholesterol molecule.

  There are five main types of steroid hormones: estrogens, progestins, androgens, glucocorticoids and mineralocorticoids. All are produced by glands or organs in the endocrine system and affect different body functions and processes.

Production

• The body's naturally occurring steroid hormones are produced by the endocrine glands. The endocrine glands are located in various parts of the body, and include the adrenal cortex, the pituitary gland, and the gonads (ovaries in women, testis in men).

  The endocrine glands synthesize, then release, the steroid hormones into the blood stream.

  Some common steroid hormones include testosterone, cortisol, estradiol and progesterone.

Function

• Steroid hormones are released into the bloodstream by the endocrine glands bound by a complex of proteins that are coded to recognize the organ or gland that the hormone has been synthesized to trigger a reaction in. When the protein complex binds with receptors on the membrane surface of the hormone's destination, the protein releases the hormone molecule into the cell. The hormone will begin a series of chemical reactions that result in the stimulation of a specific gene that will then produce an enzyme or protein designed to carry on the function that the hormone has activated.

Significance

• Steroid hormones are vital to the smooth functioning of a number of physiological functions. Steroid hormones are responsible for many of the changes in a woman's body throughout pregnancy, such as helping successfully implant the fertilized egg into the uterine wall and to prepare the breasts for milk production; they are also the substances in control of the development and growth of the sexual organs and characteristic sexual traits of both men and women.

Abuse

• Anabolic steroids are synthetically produced steroid hormones that many body builders and athletes have used to induce their bodies to put on more muscle mass in a shorter span of time than could occur naturally. Anabolic steroids are structurally related to testosterone, a steroid hormone that stimulates increased muscular development. While in small, regulated amounts they are useful for treating certain physiological disorders, anabolic steroid abuse has been linked to baldness, liver disease, certain types of cancer and heart disease.