Progesterone increases the progressive motility of human sperm

Sperm are transcriptionally inactive. Transformation from immature to mature sperm capable of fertilizing an egg depends on altering the proteome. For example, proteomic studies identified receptors not predicted to be expressed on the sperm surface, notably the progesterone receptor. This discovery raises the question of whether progesterone exerts nongenomic effects on human spermatozoa. Here we aimed to answer this question. Sperm from a normal individual were subjected to Percoll gradient centrifugation and treated with different concentrations of progesterone for 2 h at 37°C. Sperm motilities were determined using a Neubauer chamber according to the World Health Organization's standards. We measured the percentage changes in motility variables as follows: fast and straight progressive motility, slow progressive motility, nonprogressive motility, and nonmotility. Progesterone (250 ng/ml) increased sperm motility by 55.96% compared with the control without added progesterone (22.6%). Significant concentration-dependent increases in fast and progressive motility reached 29.55% compared with the control (10.1%). Progesterone (250 mg/ml) reduced the percentage of nonmotile cells to 44% compared with the control (77.4%). Progesterone increased the motility and progressive motility of human sperm in a concentration-dependent manner.