Chemical properties of a female mouse pheromone that stimulates gonadotropin secretion in males

Female mouse urine contains a pheromone that acts via the vomeronasal organ of conspecific males to stimulate a rapid increase in circulating levels of luteinizing hormone. A bioassay based on this male response was used to test biochemical preparations of female urine. Retention of significant biological activity by the urine after dialysis indicated that the activity is associated with urinary protein. Complete loss of activity from the urine after adsorption chromatography on a neutral polystyrene column suggested that the protein functions as a pheromone carrier. Assay of gel permeation chromatography fractions, before and after degradation of the urinary proteins with proteolytic enzymes, demonstrated that the protein is not necessary for the male response in the bioassay. Its resistance to vigorous proteolytic enzyme treatment further indicates that the pheromone is not a peptide. High biological activity, indistinguishable from that of the unfractionated urine, was isolated in a protein-depleted, presumably low molecular weight fraction containing compounds that are retarded by adsorption on Sephadex. The chemical properties of this female mouse pheromone are markedly different from those of a recently purified female hamster pheromone that also acts via the vomeronasal organ.