Normal Pubertal Development: Part I: The Endocrine Basis of Puberty

Brian Bordini, MD* 2. Robert L. Rosenfield, MD* 1. *Section of Adult and Pediatric Endocrinology, The University of Chicago Pritzker School of Medicine, Chicago, IL. After completing this article, readers should be able to: 1. Explain how puberty is regulated by the hypothalamic-pituitary-gonadal axis. 2. Describe the hormonal interactions involved in pubertal development in boys and girls. Puberty is a defining developmental stage of every child's life, both physically and psychosocially. Concerns about the normalcy of pubertal development and menstrual patterns are among the most common questions posed to every physician caring for children. This article reviews the primary physiologic changes in the hypothalamic-pituitary-gonadal (HPG) axis and in adrenal androgen and growth hormone (GH) production that underlie the normal pubertal milestones. Understanding of these changes allows interpretation of laboratory data in children suspected of having pubertal abnormalities. Puberty is the developmental stage during which a child becomes a young adult, characterized by the maturation of gametogenesis, secretion of gonadal hormones, and development of secondary sexual characteristics and reproductive functions. Adolescence is used widely as a generally synonymous term for puberty, but the term often is used to convey an added connotation of cognitive, psychological, and social change. Thelarche denotes the onset of breast development, an estrogen effect. Pubarche denotes the onset of sexual hair growth, an androgen effect. Menarche indicates the onset of menses and spermarche the appearance of spermatozoa in seminal fluid. Gonadarche refers to the onset of pubertal function of the gonads, which produce most of the sex hormones that underlie the pubertal changes in secondary sex characteristics. Adrenarche refers to the onset of the adrenal androgen production that contributes to pubarche. ### The Hypothalamic-Pituitary-Gonadal Axis Normal puberty results from sustained, mature activity of the HPG axis. (1). The major hormones of the HPG axis are shown in Figure …