Head Trauma and Testosterone

The pituitary gland controls the level of testosterone in the body. When the testosterone level is low, the pituitary gland releases a hormone called luteinizing hormone (LH). This hormone tells the testicles to make more testosterone. See a picture of the pituitary gland . Does this mean that fighters should be expected to be less muscular during the end of their careers, especially if they have been in a lot of wars? Evander for example has been in a lot of wars and his more built than ever. Toney himself here is shown to have way below the norrmal hormones for a person and he had massive arms and pectorals during his fights with Peter I and Peter II. Do people here suspect that those guys (and others) have juiced during the later parts of thier careers?