Abstract
Monoiodoacetate and fluoride inhibited the aerobic and anaerobic glycolysis of human spermatozoa and had a correspondingly depressing effect upon the motility of these cells. The motility was dependent upon the energy derived from the breakdown of sugar to lactic acid, and no substrate, other than utiliza-ble carbohydrate, was found effective in maintaining motility. When the spermatozoa were deprived of sugar at 38[degree]C., motility failed completely within 2-4 hrs. but could be revived again on addition of glucose if the spermatozoa had not been exposed to O2 during the period of deprivation or if they had not been inert longer than 30 mins. Time relationships were given for the loss and recovery of motility upon the withdrawal and addition of sugar. The possible application of these time relationships to the behaviour of human spermatozoa in vivo in the [male] and [female] genital tracts is discussed.