In: Anatomy and Physiology
briefly describe the mechanism of steroid hormone action and its benefits to an athlete.
Steroid hormones are
fat-soluble molecules derived from cholesterol. They are produced
by certain endocrine organs and glands and released into the
bloodstream to reach target cells. Steroid hormones include sex
hormones and adrenal gland hormones. Testosterone, estrogens, and
cortisol are examples of steroid hormones.
Steroid hormones act on cells by passing through the cell membrane,
entering the nucleus, binding to DNA, and initiating gene
transcription and protein production.
Anabolic steroid hormones are synthetic molecules that mimic the
action of testosterone. Illegal use and abuse of these hormones can
lead to a number of negative health consequences.
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 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. This is a major benefit of steroid hormone for athletes. But it is a very dangerous way to grow muscle faster this way.