[Testosterone deficit syndrome in fertile or subfertile men]

Spermatogenesis is a well defined, complex,long and very orderlyprocess of cellular division and differentiation that is under regulation by endocrine signals (GnRH, LH, Inhibin and FSH ): paracrine signals, derived from the interrelation of the various types of cells in the tubules and interstitium (even in a juxtacrine way), and autocrine signals of self communication of the cell with itself. Testosterone plays an essential role in this process. In the testicular tubules, testosterone reaches concentrations 100 times higher than circulating testosterone in the blood stream. From a reproduction point of view, we can find two completely different scenarios in relation to testosterone deficit syndrome with a similar final clinical result: The difficulties of the male to have children. On one side the presence of hypogonadism, which requires a different management depending of the clinical priority and wishes of parenthood of the patient an his partner. On the other side, the opposite situation, the patient who requires or is already under testosterone therapy. In patients with hypogonadotropic hypogonadism, when patient's clinical priority is fertility, the treatment to restore normal spermatogenesis requires external administration of gonadotropins. Treatment must be prolonged, at least 12-18 months. 95% of the cases will have a favorable response, meaning the finding of spermatozoids in ejaculation sperm as a consequence of spermatogenesis restoration.