In the adult male, GnRH, LH and testosterone are released in pulses that occur every several hours.  Follicle stimulating hormone is released in smaller pulses of longer duration.  Spermatozoa are produced by the testes by a process called spermatogenesis that requires 5 to 9 weeks, depending on the species.  The number of sperm produced each day is independent of the number ejaculated and spermatozoa are released constantly from the testes.  Spermatogenesis is a process involving sequential mitotic and meiotic divisions and concludes after differentiation of spherical spermatids into highly specialized spermatozoa.  Spermatozoa are released continually from the seminiferous epithelium.