Manipulation of bovine sperm metabolism and motility using anoxia and phosphodiesterase inhibitors

Abstract

Bovine sperm that were subjected to extended anoxia (2.5 h) in the absence of glycolytic substrates then diluted into oxygenated medium were immotile but metabolically active, producing ATP from lactate via oxidative phosphorylation. In response to anoxia sperm ATP titers dropped from 15-20 mumoles/10(8) cells to 1-2 mumoles/10(8) cells in the first 5 min then remained extremely low until reoxygenation. Cyclic AMP titers declined slowly over the anoxic period, but did not show the same scale of depression as ATP. After dilution and re-oxygenation ATP recovered 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 substantially depressed after extended anoxia in all cases; progressive motility was almost non-existent in post-anoxic sperm. Addition of isobutylmethylxanthine or Cibacron Blue F3GA, both putative phosphodiesterase inhibitors, stimulated a transient peak of cAMP, which was accompanied by motility stimulation. These techniques provide a protocol to manipulate and dissect the biochemical pathways of motility initiation in mammalian sperm.

Adenosine Triphosphate Production by Bovine Spermatozoa and Its Relationship to Semen Fertilizing Ability

“…The Clark electrode is a well‐established method for the measurement of oxygen consumption, and it has been used successfully to measure oxygen consumption of many tissues and cells, including bovine spermatozoa (Schoff and First, 1995). Cells or tissue are added to a sealed incubation chamber and stirred at high speed to ensure the even distribution of oxygen.…”

Acidification of Intracellular pH in Bovine Spermatozoa Suppresses Motility and Extends Viable Life

“…These observed differences between CO 2 -immobilized cells and sperm that were partially immobilized in DMO medium may be due in part to the lack of oxygen available to CO 2 -treated sperm cells. Schoff and First (1995) demonstrated that motility of bovine sperm was substantially depressed when cells were exposed to anoxia conditions in the absence of glycolytic substrates for more than 2.5 hours. When diluted into oxygenated medium, the sperm remained immotile but were metabolically active, producing ATP from lactate via oxidative phosphorylation.…”