NIDA for Teens: The Science Behind Drug Abuse
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Teacher's Guide

Mechanism of Action

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Anabolic steroids are taken either orally in pill form or by injection. After steroids enter the bloodstream, they are distributed to organs (including muscle) throughout the body. After reaching these organs, the steroids surround individual cells in the organ and then pass through the cell membranes to enter the cytoplasm of the cells. Once in the cytoplasm, the steroids bind to specific receptors and then enter the nucleus of the cells. The steroid-receptor complex is then able to alter the functioning of the genetic material and stimulate the production of new proteins. It is these proteins that carry out the effects of the steroids. The types of proteins and the effects vary depending on the specific organ involved. Steroids are able to alter the functioning of many organs, including the liver, kidneys, heart, and brain. They can also have a profound effect on reproductive organs and hormones.

Many of the effects of steroids are brought about through their actions in the brain. Once steroids enter the brain, they are distributed to many regions, including the hypothalamus and limbic system. When a person takes steroids, the functioning of neurons in both of these areas is altered, resulting in a change in the types of messages that are transmitted by the neurons. Since the hypothalamus has a major role in maintaining normal hormone levels, disrupting its normal functioning also disrupts the body's hormones. This can result in many problems, including a reduction in normal testosterone production in males and loss of the monthly period in females.

Similarly, steroids can also disrupt the functioning of neurons in the limbic system. The limbic system is involved in many things, including learning, memory, and regulation of moods. Studies in animals have shown that steroids can impair learning and memory. They can also promote overly-aggressive behavior and mood swings. People who take anabolic steroids can exhibit violent behavior, impairment of judgment, and even psychotic symptoms.

Other effects of taking anabolic steroids include changes in male and female sexual characteristics, stunted growth, and an increase in the amount of harmful cholesterol in the body. Anabolic steroids can also influence the growth of facial and chest hair and a cause a deepening of the voice.

The following activities, when used along with the magazine on anabolic steroids, will help explain to students how these substances change the brain and the body.