Isolation and biological activity of the multi-component sea lamprey migratory pheromone

Migratory adult sea lampreys locate spawning streams by using a pheromone released by stream-resident conspecific larvae. It was recently reported that this pheromone is comprised of a mixture of three sulfated steroids: petromyzonamine disulfate (PADS), petromyzosterol disulfate (PSDS), and petromyzonol sulfate (PS). This manuscript reports in-depth details of pheromone isolation and provides new information on the olfactory potency of PADS and PSDS and the behavioral activity of synthesized PADS. Isolation was accomplished using bioassay-guided fractionation which included liquid chromatography-mass spectrometry, electro-olfactogram recording (EOG), and behavioral assays. Both highly purified and synthesized PADS stimulated the olfactory system of adult lamprey and were attractive at concentrations of 10(-13) M. PSDS also had olfactory activity at 10(-13) M. Cross-adaptation studies with EOG recording demonstrated that PADS, PSDS, and PS are detected by independent olfactory receptor sites. Finally, the mixture of all three components was as attractive as larval water to adult sea lampreys in laboratory mazes. It is believed that these steroids are the principal components of the pheromone.