Control of superoxide and nitric oxide formation during human sperm capacitation.

We studied the modulation of superoxide anion (O(2).(-)) and nitric oxide (NO.) generation during human sperm capacitation (changes needed for the acquisition of fertility).

Reactive oxygen-induced reactive oxygen formation during human sperm capacitation.

Physiological processes are often activated by reactive oxygen species (ROS), such as the superoxide anion (O(2)(*)(-)) and nitric oxide (NO*) produced by cells. We studied the interactions between NO* and O(2)(*)(-), and their generators (NO* synthase, NOS, and a still elusive oxidase), in human spermatozoa during capacitation (transformations needed for acquisition of fertility). Albumin, fetal cord serum ultrafiltrate, and L-arginine triggered capacitation and ROS generation (NO* and O(2)(*)(-)) and superoxide dismutase (SOD) and NOS inhibitors prevented all these effects.