Aging and spermatogenesis

Abstract

Spermatogenesis, as well as the synthesis of testosterone in the human testis, is a lifelong process that persists in aging men. However, spermatogenic efficiency, estimated by the number of spermatozoa produced/day/g of testicular parenchyma (the spermatogenic index), apparently declines with age. This decline is the result of an increase in germ-cell degeneration throughout spermatogenesis, as seen in all cell types of the germ-cell line. The clinical significance of these phenomena may be questioned, since aging men still appear to be rare in infertility clinics, although parental age has increased in industrialized countries. In this context, alterations in the endocrine system are of more significance, since serum testosterone levels also appear to decrease with age. These alterations can be associated with clinical symptoms known as late-onset hypogonadism. Men suffering from this disorder can be successfully treated with testosterone; however, a broad discussion has begun regarding the necessity, usefulness, cost and risks of such a therapy in older men.