MANIPULATION OF BOVINE SPERM METABOLISM AND MOTILITY USING ANOXIA ANDPHOSPHODIESTERASE INHIBITORS

Bovine sperm that were subjected to extended anoxia (2.5 h) in the abs ence of glycolytic substrates then diluted into oxygenated medium were immotile but metabolically active, producing ATP from lactate via oxi dative phosphorylation. In response to anoxia sperm ATP titers dropped from 15-20 mu moles/10(8) cells to 1-2 mu moles/10(8) cells in the fi rst 5 min then remained extremely low until reoxygenation. Cyclic AMP titers declined slowly over the anoxic period, but did not show the sa me scale of depression as ATP. After dilution and re-oxygenation ATP r ecovered to pre-anoxia levels within 1 min, and cAMP rose to about the pre-anoxia levels. However, motility, which varied quantitatively and qualitatively between ejaculates prior to anoxic treatment, was subst antially depressed after extended anoxia in all cases; progressive mot ility was almost non-existent in post-anoxic sperm. Addition of isobut ylmethylxanthine or Cibacron Blue F3GA, both putative phosphodiesteras e inhibitors, stimulated a transient peak of cAMP, which was accompani ed by motility stimulation. These techniques provide a protocol to man ipulate and dissect the biochemical pathways of motility initiation in mammalian sperm. (C) 1995 Wiley-Liss. Inc.