How Steroid Hormones Work

Male and Female Hormones
Male and Female Hormones. JosA Carlos Pires Pereira/E+/Getty Images

Hormones are molecules produced and secreted by endocrine glands in the body. They are released into the blood and travel to other parts of the body where they bring about specific responses from specific cells. Steroid hormones are derived from cholesterol and are lipid-soluble molecules. Examples of steroid hormones include the sex hormones (androgens, estrogens, and progesterone) produced by male and female gonads and hormones of the adrenal glands (aldosterone, cortisol, and androgens).

How Steroid Hormones Work

Steroid hormones cause changes within a cell by first passing through the cell membrane of the target cell. Steroid hormones, unlike non-steroid hormones, can do this because they are fat-soluble. Cell membranes are composed of a phospholipid bilayer which prevents fat-insoluble molecules from diffusing into the cell.

Once inside the cell the steroid hormone binds with a specific receptor found only in the cytoplasm of the target cell. The receptor bound steroid hormone then travels into the nucleus and binds to another specific receptor on the chromatin. Once bound to the chromatin, this steroid hormone-receptor complex calls for the production of specific RNA molecules called messenger RNA (mRNA) by a process called transcription. The mRNA molecules are then modified and transported to the cytoplasm. The mRNA molecules code for the production of proteins through a process called translation.

These proteins can be used to build muscle.

Steroid Hormone Mechanism of Action

The steroid hormone mechanism of action can be summarized as follows:

  1. Steroid hormones pass through the cell membrane of the target cell.
  2. The steroid hormone binds with a specific receptor in the cytoplasm.
  3. The receptor bound steroid hormone travels into the nucleus and binds to another specific receptor on the chromatin.
  1. The steroid hormone-receptor complex calls for the production of messenger RNA (mRNA) molecules, which code for the production of proteins.

Types of Steroid Hormones

Steroid hormones are produced by the adrenal glands and gonads. The adrenal glands sit atop the kidneys and consist of an outer cortex layer and an inner medulla layer. Adrenal steroid hormones are produced in the outer cortex layer. Gonads are the male testes and female ovaries.

Adrenal Gland Hormones

  • Aldosterone: This mineralcorticoid acts on the kidneys promoting the absorption of sodium and water. Aldosterone aids in blood pressure regulation by raising blood volume and blood pressure.
  • Cortisol: This glucocorticoid aids in metabolism regulation by stimulating the production of glucose from non-carbohydrate sources in the liver. Cortisol is also an important anti-inflammatory substance and helps the body deal with stress.
  • Sex Hormones: The adrenal glands produce small amounts of the male sex hormone testosterone and the female sex hormone estrogen.

Gonadal Hormones

  • Testosterone: This male sex hormone is produced by the testes and in small amounts in the female ovaries. Testosterone is responsible for the development of male reproductive organs and male secondary sex characteristics.
  • Estrogens: These female sex hormones are produced in the ovaries. They promote development of female sex characteristics and skeletal growth.
  • Progesterone: This female sex hormone is produced in the ovaries and important for the production and maintenance of the uterine lining during pregnancy. Estrogen and progesterone levels also regulate the menstrual cycle.

Anabolic Steroid Hormones

Anabolic steroid hormones are synthetic substances that are related to the male sex hormones. They have the same mechanism of action within the body. Anabolic steroid hormones stimulate the production of protein, which is used to build muscle. They also lead to an increase in the production of testosterone. In addition to its role in the development of reproductive system organs and sex characteristics, testosterone is also critical in the development of lean muscle mass.

Additionally, anabolic steroid hormones promote the release of growth hormone, which stimulates skeletal growth.

Anabolic steroids have therapeutic use and may be prescribed to treat problems such as muscle degeneration associated with disease, male hormone issues, and late onset of puberty. However, some individuals use anabolic steroids illegally to improve athletic performance and build muscle mass. Abuse of anabolic steroid hormones disrupts the normal production of hormones in the body. There are several negative health consequences associated with anabolic steroid abuse. Some of these include infertility, hair loss, breast development in males, heart attacks, and liver tumors. Anabolic steroids also effect the brain causing mood swings and depression.