Correlation Between Sea Urchin Sperm Respiratory Rates and Cyclic AMP Concentrations as a Function of Cell Dilution1

Abstract

The adenosine 3'',5''-monophosphate (cyclic[c]AMP) levels and respiration rates of Strongylocentrotus purpuratus and Lytechinus pictus sea urchin sperm were estimated after various degrees of cell dilution. Dilution of L. pictus sperm caused substantial increases in both sperm cAMP levels and respiratory rates. In contrast to L. pictus sperm, cAMP levels and respiratory rates were elevated only slightly by dilution of S. purpuratus sperm. These results provide evidence for a positive relationship between endogenous cAMP levels and respiratory rates in a urchin spermatozoa.