The presence of glucose increases the lethal effect of α-chlorohydrin on ram and boar spermatozoa in vitro

Abstract

Ram cauda epididymal spermatozoa were incubated for 10 min at 34°C with or without 1.0 mM-RS-α-chlorohydrin before (1) 5 mM-D-glucose or (2) 10 mM-L-lactate plus 1 mM pyruvate or (3) 5 mM-D-glucose plus 10 mM-L-lactate plus 1 mM-pyruvate or (4) no substrate was added. Without α-chlorohydrin, the motility, the ATP concentration and the energy charge of the spermatozoa were maintained for 240 min by substrate combinations 1-3 but with no added substrate (4) the motility declined after 60 min. All the values decreased dramatically after 10 min in spermatozoa exposed to α-chlorohydrin in substrate conditions 1 and 3 (glucose present) but α-chlorohydrin had no significant effect in conditions 2 and 4 (no glucose) except after prolonged incubation. In a dose-response experiment glucose-dependent ATP dissipation began to occur with 0.025 mM-RS-α-chlorohydrin. A similar effect was seen in boar spermatozoa exposed to 0.1-5.0 mM-α-chlorohydrin and 5 mM-D-glucose. With boar spermatozoa the presence of 10 mM-L-lactate and 1 mM-pyruvate as well as glucose prevented the loss of ATP. We conclude that this concerted action of α-chlorohydrin and glucose is probably responsible for the contraceptive action of α-chlorohydrin and propose that it may depend on 'futile substrate cycling' in the glycolytic pathway.