31P nuclear magnetic resonance study of trout spermatozoa at rest, after motility, and during short-term storage

31P nuclear magnetic resonance was utilized to study respiration in spermatozoa isolated from the rainbow trout. The spectrum obtained under aerobic conditions revealed the presence of phosphomonoesters, intracellular inorganic phosphate, phosphodiesters, phosphocreatine, and free nucleotide triphosphates. The anaerobic spectrum was characterized by an increase in the inorganic phosphate resonance and by the disappearance of the phosphagen and free nucleotide triphosphate peaks. Upon reaeration, the aerobic spectrum was once again observed. Initiation of motility using fish Ringer or freshwater resulted in a decrease in phosphocreatine and nucleotide di- and tri-phosphate levels along with an increase in inorganic phosphate. The presence or absence of a phosphagen peak seemed to be correlated with motility. Preliminary studies on short-term storage of spermatozoa were also performed. These findings are analyzed in terms of the maintenance of motility in the spermatozoa of fish and some invertebrates.