Adrenocortical Function in Puberty: Serum ACTH, cortisol and dehydroepiandrosterone in girls and boys. Acta Paediatr Scand, 68: 599, 1979.-Serum ACTH, cortisol and dehydroepiandrosterone (DHEA) were determined in 200 girls and 80 boys. In girls, serum DHEA showed significant increases between all bone age groups from the youngest one, 7.5 years, to 12.5 years. A plateau was then seen up to 15.5 years of age, followed by a continuous increase to the oldest group (18.5 years). In boys, a progressive increase in DHEA was also seen from the youngest age group (8.5 years), but a period of a more rapid increase did not commence until after 12.5 years of age and it then continued to the oldest group. The level of DHEA in boys was significantly lower than in girls until the oldest group, in concert with the earlier pubertal development in girls. The importance of DHEA in initiating the early physical signs of normal puberty seems also to be different in the two sexes, since serum DHEA in girls was almost double that seen in boys, when compared according to the stage of pubic hair growth. Serum cortisol showed a small progressive increase in girls, the concentrations postmenarche being significantly higher than premenarche. In boys, a decrease was seen up to 12.5 years of age and an increase occurred from 16.5 years onwards. In both sexes, ACTH and cortisol levels showed an inverse but nonsignificant relationship to each other. Serum ACTH levels in the different age groups showed no significant changes.