Examining Male Infertility

Susanne Quallich


Urol Nurs. 2006;26(4):277-288. 

In This Article

Development of Sperm

Males do not begin to produce sperm until puberty, when testosterone begins to exert its influence on overall male development and growth. Spermatogenesis is driven by testosterone production in the Leydig cells of the testes. Under the influence of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which are released from the anterior pituitary, the testes begin to produce sperm in a four-step process of development: spermatogonia, spermatocyte, spermatid, spermatozoon. This cycle takes roughly 74 days to complete, with an additional 12 days for final maturation as the sperm traverse the length of the epididymis (Sigman, Lipshultz, & Howards, 1997). The duration of this cycle is important, as any changes in the semen analysis following medical or surgical intervention will not be reflected for at least 3 months.

This process is governed by a negative feedback loop, with testosterone acting as the primary negative feedback component that slows LH and FSH secretion. Inhibin, released during spermatogenesis, also specifically inhibits activity or down-regulates FSH. This feedback system can be overridden by the administration of exogenous testosterone, or medications such as luteinizing hormone-releasing hormone antagonists, both of which stop the body's own production of testosterone (and halt spermatogenesis as well).


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