Other Interactions - Estrogen and DHT
It is also true that the testosterone molecule is also acted upon in the bloodstream by other elements - certain enzymes, which will result in the formation of other new active steroid hormones. Typically we are mostly interested in two of the primary metabolites of this conversion process brought about by these enzymes, which we cover in greater detail later in the book. These two metabolites are estrogen (the female sex hormone) and dihydrotestosterone or DHT, which is another androgen. Estrogen, as mentioned, is typically a female classified hormone, but is present in both sexes and chemically is very similar in structure to the androgen hormone testosterone. It is with the presence and action of the enzyme aromatase, which we shall look closely at in later chapters, that a form of estrogen (estradiol) is produced in the male body. Now the primary site for activity of the aromatase enzyme within the male body is in the adipose (fat) tissues, as well as in the liver, testes and various regions of the central nervous system. For the average and typical healthy male, this natural estrogen production does not pose any real problems or alterations to ones physical disposition. In much higher quantities however, the increased levels of estrogen in the male will result in some of the anabolic steroids typical core side effects such as water retention, female breast tissue development and body fat accumulation. As you can imagine, these side effects will dramatically alter an athletes phsique.


Now tissues in the prostate, skin and scalp are the key areas where concentrations of the active enzyme 5Alpha-Reductase, which is responsible for the conversion of testosterone into dihydrotestosterone. This is a very potent androgen metabolite which in high concentrations can result in oily skin, acne and/or the aggravation of male-pattern baldness. Again, we will look at this enzyme and its process in the body in later chapters.