The Source of H2O2 for the Uterine Fluid-Mediated Sperm-Inhibitory System12

Abstract

Lactobacillus acidophilus, a H₂O₂-generating organism commonly found in the vaginal canal, can substitute for reagent H₂O₂ in the uterine fluid-mediated sperm-inhibitory system. Lactobacilli also can inhibit sperm motility by producing a fall in pH. Spermatozoa form H₂O₂ particularly in the presence of certain amino acids (L-phenylalanine, L-tryptophane, L-methionine, L-tyrosine, L-monoiodotyrosine, L-diiodotyrosine, L-dibromotyrosine). The H₂O₂ formed by spermatozoa in the presence of L-phenylalanine can be utilized as a component of the uterine fluid-iodide (or thiocyanate)-H₂O₂ sperm-inhibitory system. The presence of a peroxidase-mediated sperm-inhibitory system in human secretions is considered.