Institute of Chemistry and Biology of the Marine Environment, Universität of Oldenburg, 26111 Oldenburg, Germany.
In the marine polychaete Platynereis dumerilii (Audouin and Milne-Edwards, 1833; Polychaeta: Nereida) the reproductive behaviour in the two sexes is synchronised by a consecutive discharge of sex-specific pheromones. The female discharges one pheromone to induce the sperm release of swarming males. Zeeck et al. (1998) identified this sperm release pheromone as uric acid. Prior the body fluid was confirmed as the source of this putative sex pheromone, but our latest investigation gave rise to doubts about the presentation. We derived coelomic fluid free from tissue residues of ripe females by a new technique. In bioassays these crude samples effected no sperm release nor any change on males swarming behaviour. The analysis of this coelomic fluid, performed by ultrafiltration and high-performance liquid chromatography (HPLC), showed not any uric acid. In samples obtained by the liquid extraction of the female bodies with millipore water by treating in an ultrasonic bath at 0°C, uric acid was identified by HPLC as one compound. Bioassayed males performed their characteristic reproduction behaviour after adding this body extract. Quantification of the uric acid in the body extract yielded 4.6 µg per female. This is the same amount as reported earlier. These results suggested, that coelomic fluid does not represent the source of sperm release pheromone uric acid of Platynereis dumerilii.