Testosterone was often referred to as the "male" hormone, because it is responsible for developing some of the male characteristics such as lowering of the voice and hair growth, and because the male body produces much more of it than the female.
Testosterone in the male is produced mainly in the testis, a small amount being produced in the adrenal. It is synthesized from cholesterol. The regulation of its production may be simplified thus: the hypothalamus (part of the brain) produces gonadotrophin releasing hormone (GnRH) which acts on the anterior pituitary to increase the production of luteinizing hormone (LH) and follicle stimulating hormone (FSH). LH acts on the Leydig cells in the testis, causing them to produce testosterone. FSH, together with testosterone act on the Sertoli cells in the testis to regulate the production and maturation of spermatozoa. Testosterone in turn acts on the hypothalamus and anterior pituitary to suppress the production of GnRH, FSHand LH, producing a negative-feedback mechanism which keeps everything well-regulated. The small amount produced in the adrenal (in both sexes) is regulated by secretion of adrenal corticotrophin hormone (ACTH), also secreted by the pituitary.
Testosterone, and its metabolites such as dihydrotestosterone, act in many parts of the body, producing the secondary sexual characteristics often male: balding, facial and body hair, deep voice, greater muscle bulk, thicker skin, and genital maturity. At puberty it produces acne, the growth spurt and the enlargement of the penis and testes as well as causing the fusion of the epiphyses (through its conversion to estrogens), bringing growth in height to an end. It plays some role in maintaining the sexual organs in the adult, but only a low concentration is required for this.
The normal production of testosterone in the adult male is 4 to 9mg per day. The normal plasma concentration is 22.5nmol/l, of which 97% is protein bound. Most is excreted in the urine as 17-keto steroids, but a small amount is converted to estrogen's.
The history of steroids
Steroids was developed in the 1940s in Germany and used experimentally on their troops during World War II, the drugs ability to stimulate tissue growth and protein synthesis lead them to believe that the drug might be beneficial to treat burn victims and towards other war accidents. The drug was never such a big success, because other drugs with fewer side effects were discovered, and the legal use of steroids still seems to be declining.
The legal use of steroids
Steroids are used for treating anemia, because of it's ability to increase the production of red blood corpuscles (red blood cells). They are also used for treatment of leukemia, cancer mammae, and at times steroids are also used for general strengthening therapy. Steroids have also been tried in combination with other drugs as a means of helping AIDS patients.
Why use steroids?
Enhanced recuperation / Reduced recovery time Strength increases Reduced body fat Enlarged muscle size Many of these effects are only temporary, which means that once you get off steroids most of the gains disappear. As mentioned before steroids causes water retention, so steroid users will gain mass very quickly, but most of it will be water not muscles.
This will put the body through a lot of stress, loosing and gaining weight in cycles. The more positive sides of steroids are that they seem to be able to suppress the body's production of the stress hormone cortisol after exercise. Cortisol is actually a muscle tissue destroyer, so by keeping the levels of cortisol down reduces muscle damage and allows for faster recuperation. So the steroid user might be able to train more frequent.
Another major effect of steroids is the increased stimulation of the protein synthesis by increasing the amount of nitrogen in the body, more protein available to the body means that the environment for muscle production is better.
A lot of steroid users report that the steroids help them lower their body fat levels, the reason for this is not clear, but some feel it is because of an increased metabolic rate. Others claim that oxidation of fat is increased because the steroids promote mitochondria growth in the cells.
Oral vs. injectable
Injectable steroids are longer lasting in the body, but therefore they can be detected in your body for a longer period of time, so athletes that are likely to be doping tested have shifted from using injectables to orals.
The problem with orals however, aside from the fact that they are not as long lasting, is that they put a lot of strain on the liver as they must be processed there. Larger quantities are also needed as a lot of it is broken down before it enters the bloodstream.