Howard Hughes Medical Institute investigator Catherine Dulac and colleagues Hayan Yoon, an HHMI predoctoral fellow, and Lynn W. Enquist published their findings in an immediate early publication on November 10, 2005, in the journal Cell. Yoon and Dulac are at Harvard University, and Enquist is at Princeton University. Related studies by HHMI investigator Linda B. Buck are published in the same issue.
The pheromone communication system, which is found in a wide range of mammals, involves detection of chemical odorants released by animals. Pheromones are chemicals that are involved in changing behavior or hormone secretion. According to most biology textbooks, detection of pheromones takes place in a specialized structure, called the vomeronasal organ (VNO). Although the VNO resides in the nasal cavity, the pheromone sensory system is distinct from the sense of smell, as are the chemical receptors involved. In animals possessing a pheromone sensory system -- including mice, dogs, cats, and elephants -- the system governs a range of genetically preprogrammed mating, social ranking, maternal, and territorial defense behaviors.
In their experiments, Dulac and her colleagues sought to determine whether sensory neurons in the main olfactory epithelium and the VNO were connected to neurons in the brain that synthesize luteinizing hormone releasing hormone (LHRH). LHRH controls the onset of puberty. In females it also stimulates ovulation and controls the estrus cycle. In males, the hormone controls gonad function, including spermatogenesis and testosterone production.