ABSTRACT
Puberty is the transitional period between the juvenile state and adulthood during which the adolescent growth spurt occurs, secondary sexual characteristics appear, fertility is achieved, and profound psychological changes take place. The specific mechanisms involved in the timing of puberty are complex and poorly understood. The average age at onset of puberty shows a secular trend over the past century toward earlier occurrence, cutting across geographic and ethnic lines. There are two patterns of gonadotropin secretion: tonic and cyclic. Tonic or basal secretion is regulated by negative or inhibitory feedback mechanisms: Changes in the concentration of circulating sex steroids, and possibly “inhibins” result in reciprocal changes in secretion of pituitary gonadotropins. After the fall in sex steroids, especially estrogens, during the first days after birth, the concentration of Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH) increases and exhibits wide perturbations during the first months of life.
