Anabolic steroids are synthetic substances related to male sex hormones (androgens). Although it is illegal in the United States to possess or distribute anabolic steroids for nonmedical use, a "black market" for them exists, and many amateur and professional athletes take them to enhance performance. In many cases, the athletes take doses that are extremely high—perhaps 100 times the doses that might be prescribed for medical use. As a result, they put themselves in real danger of short-term and long-term health problems. Blood testing, as has been used in the Olympic Games, can detect, identify, and quantify the presence of anabolic steroids in the blood of athletes, which can lead to the disqualification of an athlete.
Steroid isolation , depending on context, is the isolation of chemical matter required for chemical structure elucidation, derivitzation or degradation chemistry, biological testing, and other research needs (generally milligrams to grams, but often more  or the isolation of "analytical quantities" of the substance of interest (where the focus is on identifying and quantifying the substance (for example, in biological tissue or fluid). The amount isolated depends on the analytical method, but is generally less than one microgram.  [ page needed ] The methods of isolation to achieve the two scales of product are distinct, but include extraction , precipitation, adsorption , chromatography , and crystallization . In both cases, the isolated substance is purified to chemical homogeneity; combined separation and analytical methods, such as LC-MS , are chosen to be "orthogonal"—achieving their separations based on distinct modes of interaction between substance and isolating matrix—to detect a single species in the pure sample. Structure determination refers to the methods to determine the chemical structure of an isolated pure steroid, using an evolving array of chemical and physical methods which have included NMR and small-molecule crystallography .  :10–19 Methods of analysis overlap both of the above areas, emphasizing analytical methods to determining if a steroid is present in a mixture and determining its quantity. 
Neural injections of Bromodeoxyuridine (BrdU) were applied to males of both groups to test for neurogenesis . Analysis showed that testosterone and dihydrotestosterone regulated adult hippocampal neurogenesis (AHN). Adult hippocampal neurogenesis was regulated through the androgen receptor in the wild-type male rats, but not in the TMF male rats. To further test the role of activated androgen receptors on AHN, flutamide , an antiandrogen drug that competes with testosterone and dihydrotestosterone for androgen receptors , and dihydrotestosterone were administered to normal male rats. Dihydrotestosterone increased the number of BrdU cells, while flutamide inhibited these cells.