Changes in adenosine 5'-triphosphate, adenylate energy charge and adenosine 3'5'-cyclic monophosphate during the freezing of buffalo semen

In freshly ejaculated buffalo semen (N = 4) there were 24.61 +/- 5.28 nmol ATP and 40.39 +/- 5.94 nmol total adenylate/10(8) spermatozoa, and 97.75 +/- 7.06 pmol cAMP/10(9) spermatozoa. The semen was frozen in 4 steps (I, dilution; II, cooling; III, glycerolization and equilibration; IV, freezing and thawing). Motility, ATP, total adenylate and cAMP were significantly lower after Step IV than after Step I. Motility and ATP concentration were significantly correlated in egg-yolk--Tris (r = 0.530, P less than 0.05), skim milk--egg yolk (r = 0.754, P less than 0.01), egg yolk--citrate--glucose (r = 0.784, P less than 0.01) and citric acid--whey (r = 0.551, P less than 0.05). Cyclic AMP and motility in egg yolk--Tris were also correlated (r = 0.714, P less than 0.01). The adenylate energy charge was stable in all 4 freezing steps.