Human chorionic gonadotropin-based clinical treatments for infertile men with non-obstructive azoospermia

Spermatogenesis is primarily controlled by follicle-stimulating hormone and luteinizing hormone-driven testosterone. Luteinizing hormone acts on the Leydig cells, stimulating steroid production, predominantly testosterone, and activating critical inter-related spermatogenesis regulatory pathways. Despite evidence that exogenous gonadotropins containing luteinizing hormone activity, particularly human chorionic gonadotropin, can effectively restore spermatogenesis in azoospermic males with hypogonadotropic hypogonadism, the use of these drugs to treat other forms of non-obstructive azoospermia is the subject of an ongoing debate. In this review, we delve into the molecular properties and functions of human chorionic gonadotropin in spermatogenesis regulation and explore available preparations for therapeutic use. We examine the evidence regarding the effectiveness of human chorionic gonadotropin in treating infertility in men with pre-testicular or testicular non-obstructive azoospermia and, additionally, identify the main areas for future research. Our review highlights the critical role of luteinizing hormone activity in spermatogenesis and emphasizes the potential of human chorionic gonadotropin in treating male infertility. The variation in the characteristics of patients with non-obstructive azoospermia underscores the importance of assessing hormonal profiles when contemplating hormonal treatment for these patients. A novel stratification of male infertility patients, the APHRODITE criteria, which considers clinical and laboratory indicators, may assist in identifying individuals who could benefit from human chorionic gonadotropin therapy. While accumulating evidence suggests promising venues for pharmacological treatment in male infertility, including non-obstructive azoospermia, further research is required to completely elucidate the mechanisms underlying the effects of exogenous gonadotropins with luteinizing hormone activity on sperm production and to establish the most effective dosages and treatment durations.