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Changes in hypothalamic-pituitary-gonadal endocrine function
lead to the striking changes associated with secondary sexual development.
Endocrine changes of puberty are divided into (1) gonadarche, or
the awakening of gonadal action during which increased pituitary gonadotropins
cause the secretion of gonadal steroids, and (2) adrenarche, or
the awakening of adrenal androgen secretion caused by still undefined
factors.
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Stages of pubertal development are described using a sexual
maturity rating scale popularized by Tanner. Staging provides
an objective, consistent description of physical development (Fig. 540-1). Breast development (caused by ovarian
estrogens) and pubic hair development (caused by adrenal androgens)
are usually, but not always, coordinated in girls (eg, premature
adrenarche or premature thelarche) so that each should be documented.
Similarly, in boys, testicular/penile development and pubic
hair development may not be synchronous because the adrenal gland
can produce its own androgens out of sequence with testicular androgen
secretion, due to either adrenal disease or adrenarche.
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