Adrenarche - Role in Puberty

Role in Puberty

An initiator of adrenarche has not yet been identified. Researchers have unsuccessfully tried to identify a new pituitary peptide, to be called "adrenal androgen stimulating hormone". Others have proposed that adrenarchal maturation is a gradual process intrinsic to the adrenal glands that has no distinct trigger. A third avenue of research is pursuing a possible relationship with either fetal or childhood body mass and related signals such as insulin and leptin. Many children born small for gestational age (SGA) because of intrauterine growth restriction (IUGR) have an earlier onset of adrenarche, which raises the possibility that timing of adrenarche may be affected by physiological programming in infancy. Adrenarche also occurs prematurely in many children who are overweight, suggesting a possible relationship with body mass or adiposity signals.

The principal physical consequences of adrenarche are androgen effects, especially pubic hair (in which Tanner stage 2 becomes Tanner stage 3) and the change of sweat composition that produces adult body odor. Increased oiliness of the skin and hair and mild acne may occur. In most boys, these changes are indistinguishable from early testicular testosterone effects occurring at the beginning of gonadal puberty. In girls, the adrenal androgens of adrenarche produce most of the early androgenic changes of puberty: pubic hair, body odor, skin oiliness, and acne. In most girls the early androgen effects coincide with, or are a few months behind, the earliest estrogenic effects of gonadal puberty (breast development and growth acceleration). As female puberty progresses, the ovaries and peripheral tissues become more important sources of androgens.

Parents and many physicians often infer (incorrectly) the onset of puberty from the first appearance of pubic hair (termed pubarche). However, the independence of adrenarche and gonadal puberty is apparent in children with atypical or abnormal development, when one process may occur without the other. For instance, adrenarche does not occur in many girls with Addison's disease, who will continue to have minimal pubic hair as puberty progresses. Conversely, girls with Turner syndrome will have normal adrenarche and normal pubic hair development, but true gonadal puberty never occurs because their ovaries are defective.