Growth hormone levels rise steadily through normal puberty, in parallel with the pubertal stages but decline rapidly at the end of puberty (stage V). The general evolution of the secretory profile of GH is parallel to the growth velocity curve. The frequency of GH pulses remains unchanged; however, their amplitude, mean integrated concentrations, area under the curve, and urinary growth hormone are elevated at midpuberty. The main action of GH is to ensure, together with sex steroids, the pubertal growth spurt. However, the role of pubertal GH is not confined to inducing the pubertal growth spurt. It also participates, together with sex steroids, in the acquisition of adult bone mineral density.