Observations on the Content of Atp and Adp in Bull Spermatozoa Using the Firefly Luciferase System

The development of a method to measure small amounts of nucleotides would be of considerable value in experiments concerned with metabolism in mammalian spermatozoa. As the adenine nucleotides have been shown to be the predominant nucleotides in mammalian spermatozoa (Brooks, 1970), measurement of ATP and ADP by the luciferin-luciferase system appeared to be a method ideally suited to this purpose. Ejaculated bull semen, collected by artificial vagina, was used in the present work. The measurement of ATP was carried out in a Packard Model 3380 liquid scintillation spectrometer calibrated according to Stanley & Williams (1969). The phosphate buffer described by these workers was altered to include 2 mm-EDTA and 2 mm-2-mercaptoethanol. In addition, the luciferin-luciferase preparation made up in arsenate buffer was incubated with apyrase to reduce background luminescence