Puberty, that awkward phase when boys and girls are primed for their sexual reproductive years as men and women, appears to be triggered by the brain's own version of "It takes two to tango," whereby a signal literally gets turned on by a molecule that is produced by a gene aptly named KiSS-1.
The couple – a biochemical equivalent to Adam and Eve – makes its sudden appearance in a region of the brain called the hypothalamus just as puberty begins, according to a study published in this week's online edition of the Proceedings of the National Academy of Sciences (PNAS).
Until now, little had been known about what instigates the cascade of hormone secretions that, over time, produces puberty's tell-tale physical changes, including the development of breasts in girls and voice change in boys. As such, this research begins to answer one of the most vexing questions about human development: What causes puberty to begin? How is it that the full repertoire of reproductive hormones can exist at birth, go into hiding at about four to six months of age, then reemerge in full force some 10 to 12 years later?
"Puberty is critical to human development. And while there is a fairly good understanding of how the endocrine system regulates the hormones involved, just how and when the brain activates this process has been a great mystery. An appreciation of puberty's deep-seated neurobiological mechanisms could, for instance, help prevent precocious or delayed puberty from occurring in some children," noted the study's lead author, Tony Plant, Ph.D., a professor in the departments of cell biology and physiology and obstetrics, gynecology and reproductive sciences, as well as director of the Center for Research in Reproductive Physiology at the University of Pittsburgh School of Medicine.
The research, performed in collaboration with teams at Harvard University's Massachusetts General Hospital and the Oregon National Primate Research Center, builds on the discovery made independently by both Harvard and French researchers that a gene called GPR54 is defective in children with a rare disorder that inhibits puberty's onset. To better understand what role GPR54 plays in the initiation of puberty, as well as learn about KiSS-1, which in earlier rodent studies had been identified as a molecule that activates a signal receptor of GPR54, the researchers looked to the nonhuman primate, the only animal with a reproductive system in common with the human's.