Abstract
Puberty/adolescence is a transition between childhood and adulthood, after which reproductive, cognitive, emotional, and social maturations are attained. My talk will focus on the recent progress on the mechanism of the onset of puberty and further review current knowledge on brain development during adolescence. Puberty is a consequence of hypothalamic maturation. An increase in pulsatile LHRH release from the hypothalamus triggers the onset of puberty. Tonic GABA inhibition suppresses LHRH neuronal activity throughout juvenile period. Its reduction shortly before puberty leads to an increase in glutamatergic activity resulting in the pubertal increase in LHRH release. In addition, the role of GPR54 and kisspeptin (metastin54) have been introduced into this scheme. Nonetheless, it is unclear what decreases tonic GABA inhibition shortly before puberty and how the kisspeptin/GPR54 neuronal system fits into the pubertal changes in GABA and glutamate neuronal activity. Brain imaging data in humans show that maturation of neocortical and limbic circuits occurs throughout puberty completing in the early twenties. The pubertal increase in gonadal steroids would greatly influence the maturation of their circuits, although the degree to which gonadal steroids are involved in adolescent brain development is still unknown. Collectively, despite the recent progress in understanding the puberty brain and adolescent brain, further research with collaboration between reproductive neuroendocrinologists, behavioral scientists, and brain imaging specialists is required to illustrate brain development during the pubertal/adolescent period. [J Physiol Sci. 2008;58 Suppl:S3]
