HIGH-ENERGY PHOSPHATE-COMPOUNDS IN SPERMATOZOA OF THE SEA-URCHINS ARBACIA-LIXULA AND PARACENTROTUS-LIVIDUS

Changes in the levels of high-energy phosphate compounds following inc ubation in seawater were measured in spermatozoa of the sea urchins Ar bacia lixula and Paracentrotus lividus, which belong to the orders Arb acioida and Echinoida, respectively. Following incubation in seawater, the levels of ATP in both A. lixula and P. lividus spermatozoa decrea sed rapidly. In contrast, a remarkable increase in AMP levels was obse rved, although ADP levels changed slightly. A. lixula and P. lividus s permatozoa contained high concentrations of creatine phosphate, but ar ginine phosphate was present at a trace level. The creatine phosphate levels in these spermatozoa decreased immediately following incubation in seawater. There were high activities of creatine kinase and adenyl ate kinase in A. lixula and P. lividus spermatozoa. However, arginine kinase activity could not be detected. These results suggest that crea tine phosphate is able to substitute for ATP in both A. lixula and P. lividus spermatozoa. It is also possible that not only the creatine-ph osphate shuttle but also adenylate kinase plays an important role for ATP supply to use their flagellar motility.