Development of children and adolescents: physiological, pathophysiological, and therapeutic aspects.

Luteinizing hormone (LH) secretion is pulsatile with nocturnal augmentation even in prepubertal children, though at very low concentrations. With puberty wake-time, LH concentration increases 100-fold. Rising estradiol levels transiently increase growth hormone (GH) concentrations, which in turn leads to increases in insulin-like growth factor (IGF)-I, insulin resistance, and physiological hyper-insulinemia. In addition to estrogens, GH-IGF are important in accretion of bone mineral density (BMD) in puberty, and hypofunction may cause permanent low bone density. Growth hormone treatment of girls with Turner syndrome increases final height.