Maintenance of Motility in Human Spermatozoa by Energy Derived through Oxidative Phosphorylation and Addition of Albumin

Abstract

The motility of and ATP concentrations in twice-washed human ejaculated spermatozoa have been found to be well maintained for at least 4 h in a Ca²⁺-free Krebs Ringer phosphate buffer containing either no added substrate or succinate (10 mM), L-acetyl carnitine (5 mM) + L-malate (5 mM), L-lactate (10 mM) or glucose (5 mM). Inclusion of human serum albumin (3% w/v) into the medium considerably enhanced the motility but did not alter ATP concentrations in the spermatozoa. There was no significant advantage of any of the substrates to the spermatozoa for maintenance of motility, but glucose and succinate were associated with higher ATP concentrations. It is concluded that the beneficial effects of albumin on spermatozoa motility were not due to maintenance of higher ATP concentrations.

Treatment of spermatozoa suspensions with oligomycin (8 µm), except those incubated with glucose, completely inhibited motility and reduced ATP concentrations to near zero within 30 min. This further confirmed that energy is available to human spermatozoa for maintenance of motility and viability through respiratory linked oxidative phosphorylation as well as substrate level phosphorylation.

Incubations were also carried out in Tris based salts media, but these were not found to support motility of spermatozoa satisfactorily for more than 6-120 min. This was, however, not related to ATP production.