In androgen-responsive target tissues such as the skin, scalp, and prostate, the high relative androgenicity of testosterone is dependant on its reduction to dihydrotestosterone (DHT). The 5-alpha reductase enzyme is responsible for this metabolism of testosterone. The concurrent use of a 5-alpha reductase inhibitor such as finasteride or dutasteride will interfere with site-specific potentiation of testosterone action, lowering the tendency of testosterone drugs to produce androgenic side effects. It is important to remember that both anabolic and androgenic effects are mediated via the cytosolic androgen receptor. Complete separation of testosterone’s anabolic and androgenic properties is not possible, even with total 5-alpha reductase inhibition.
When taken for more than 4-6 weeks, it can increase body mass and protein anabolism. However, buy testosterone cypionate uk for the body to build muscle one also has to eat a diet rich in calories. Most bodybuilders also take a combination of other hormones at the same time. Because testosterone is converted to estrogen in the fatty tissues, there is always the chance of developing gynecomastia and water retention. To prevent this, most bodybuilders add Arimidex or tamoxifen during the off cycle.
During testosterone injections, the natural body testosterone release is inhibited by feedback mechanism through inhibition of pituitary LH. At large doses, even spermatogenesis can be impaired. To allow for the hypothalamic-pituitary axis to recover, it is highly recommended that the drug be tapered off slowly over a period of a few weeks. Sudden discontinuation of the drug can lead to extreme fatigue clit tumblr , weight loss and susceptibility to fractures.
The effects of testosterone in humans and other vertebrates occur by way of two main mechanisms: by activation of the androgen receptor (directly or as DHT), and by conversion to estradiol and activation of certain estrogen receptors. Free testosterone (T) is transported into the cytoplasm of target tissue cells, where it can bind to the androgen receptor, or can be reduced to 5α-dihydrotestosterone (DHT) by the cytoplasmic enzyme 5α-reductase. DHT binds to the same androgen receptor even more strongly than T, so that its androgenic potency is about times that of T. The T-receptor or DHT-receptor complex undergoes a structural change that allows it to move into the cell nucleus and bind directly to specific nucleotide sequences of the chromosomal DNA. The areas of binding are called hormone response elements (HREs), and influence transcriptional activity of certain genes, producing the androgen effects.