ATP contents of human semen, seminal plasma and isolated sperm at time intervals after ejaculation.

1. ATP was estimated in 105 samples of human semen, seminal plasma and sperm of normozoospermic and oligozoospermic origins at time intervals after ejaculation. 2. In semen with sperm counts up to 40 millions per ml and in seminal plasma, ATP levels were lower than in specimens with higher sperm counts. 3. In isolated sperm, the ATP content decreased with the increase in sperm density. 4. The decrease in ATP after 24 hr was the highest in sperm, lower in semen and the lowest in seminal plasma, being maximal in specimens with high sperm counts.