Recent topics related to testosterone deficiency syndrome in Japan.

Androgens, the levels of which decrease with ageing, play many physiological roles in various organs. Testosterone deficiency syndrome (TDS) has received widespread attention in the last several years. First-line treatment for TDS should be testosterone replacement therapy (TRT), which is reported to improve several TDS symptoms. Recently, a clinical practice manual for TDS was written and published by a collaborative team from the Japanese Urological Association and the Japanese Society for the Study of the Aging Male to recommend standard procedures for the diagnosis, treatment, prevention and monitoring of adverse reactions to TRT and for post-treatment assessment. In this manual, intramuscular injection of testosterone enanthate or human chorionic gonadotropin and the testosterone gel 'Glowmin' were recommended as TRT. Currently, two topics related to TDS are being focused on in Japan: the relationship between TDS and metabolic syndrome and treatment options for eugonadal patients with TDS symptoms. In this review, the possibility of TRT for metabolic syndrome as well as the relationship between testosterone and adiponectin, which is a key molecule in metabolic syndrome, is discussed. Finally, the possibility of herbal medicines as a treatment option for patients with TDS is addressed, especially for eugonadal patients, because eugonadal men with TDS symptoms account for approximately 30% of the general population. The increase in the levels of several cytokines, such as IL-8, IL-13, interferon-γ and tumor necrosis factor-α, after herbal medicine treatment may be the reason for this efficacy.