On the use of adenosine triphosphate for estimation of motility and energy status in human spermatozoa.

Following the development of a reliable technique for analysis of total ATP in semen, the ATP concentration of untreated human ejaculates was compared with progressive sperm motility during 3 continuous days following ejaculation. As correlation was poor between these variables, spermatozoa were separated by self-migration on Percoll gradients and washed free of Percoll solution. ATP concentration and sperm motility was then assessed. Aliquots of separated sperms were transferred to separate tubes, and increasing concentrations of sera were added prior to incubation at 37 degrees C for 4 days. Under these conditions a good correlation between specific progressive motility and specific ATP content was found (r = 0.88). A high concentration of human blood serum (10% v/v) was found to be necessary for maintainance of motility, but neither the addition of bovine serum albumin nor an increase in the glucose concentration had any effect on sperm motility or on the ATP concentration. Addition of different fractions of human blood serum indicated that the components mainly responsible for maintaining sperm motility are greater than 10,000 daltons. Our findings strongly indicate that ATP assessment can be used to estimate the energetic condition of a human sperm population after its separation from seminal plasma. It is suggested that this in vitro system can be used to define optimal conditions for sperm function.