SPERM MOTILITY AND KINETICS OF DYNEIN ATPASE IN ASTHENOZOOSPERMIC ANDNORMOZOOSPERMIC SAMPLES AFTER STIMULATION WITH ADENOSINE AND ITS ANALOGS

We tested the effects of adenosine and 2-deoxyadenosine on the activat ion of human spermatozoa, In the asthenozoospermic group of patients a denosine produces an increase in sperm motility from 33.3 +/- 2.1% to 42.1 +/- 3.4%, progressive motility from 22.5 +/- 1.3% to 28.6 +/- 1.7 % and forward progression rating from 2.1 +/- 0.2% to 2.8 +/- 0.1%. 2- Deoxyadenosine stimulated asthenozoospermic samples to a greater degre e than adenosine. Sperm motility rose to 48.9 +/- 3.4%, progressive mo tility to 32.1 +/- 3.4% and forward progression rating to 3.0 +/- 0.1% following stimulation with 2-deoxyadenosine. The kinetic parameters a nd basic characteristics of dynein ATPase were determined. The maximum activity of dynein ATPase, V-max, was significantly different (P < 0. 001) for asthenozoospermic and normozoospermic samples: 6.46 +/- 2.1 n mol P-i/mg/min and 16.99 +/- 3.7 nmol P-i/mg/min respectively. However , the enzyme affinity for ATP was not different. Stimulation of asthen ozoospermic samples with adenosine and 2-deoxyadenosine caused an incr ease of V-max (70-90% and 90-110% respectively) and no significant cha nge in K-M was observed. In order to block the nucleoside transporter and to eliminate the action of adenosine inside the cell, dipyridamole was used but the effects of adenosine were not neutralized. 5'-(N-eth ylcarboxyamido)-adenosine showed effects similar to those of adenosine , even when applied in 1 mu M concentration. These results indicate th at adenosine and its analogues stimulate sperm motility and activity o f dynein ATPase, most probably via A(2) receptors.