The study is designed to identify and validate new protein biomarkers in blood related to testosterone activity. Thirty healthy young males underwent pharmaceutical castration to lower testosterone levels. After three weeks the subjects received an intramuscular injection of testosterone undecanoate. Blood samples from just before pharmaceutical castration, three weeks after castration, and one week after injection of testosterone undecanoate were collected representing normal testosterone levels, low testosterone levels, and testosterone at eugonadal levels.

Inclusion Criteria:

healthy males

Exclusion Criteria:

use of anabolic steroids, use of narcotics,