Effect of prostaglandin F2 alpha and methylxanthines on enzymic release of bull epididymal spermatozoa in vitro.

The in vitro effect of PGF2 alpha and methylxanthines (theophylline and caffeine) on enzymatic release of bull epididymal spermatozoa was investigated. Epididymal spermatozoa were diluted with egg yolk citrate-based diluent to a concentration of 50 x 10(6) spermatozoa per ml. Aliquots were supplemented with PGF2 alpha at levels of 0, 300, 600 and 1200 micrograms/ml, theophylline or caffeine was added at levels of 0, 500 and 1000 micrograms/ml and incubated at 37 degrees C for 4 h. Spermatozoal motility was decreased with increasing level of PGF2 alpha and the activities of transaminases in the extracellular medium showed a continuous increase. Addition of theophylline or caffeine at both dose levels significantly increased the sperm motility; the activities of transaminases either were not significantly changed or were significantly decreased during the 4 h incubation. These results suggest that supplementation of bull spermatozoa with high levels of PGF2 alpha suppressed motility and induced sperm membrane damage and permeability. However, supplementation of bull spermatozoa with methylxanthines enhanced sperm motility and was not harmful to the integrity of the sperm membrane.