Adrenarche is a developmental change of the adrenal gland that results in increased secretion of adrenal androgens. This maturational process generally begins several years before activation of the hypothalamic-pituitary-gonadal axis (gonadarche). To study further the relationship between adrenarche and gonadarche, we examined adrenarche in patients with precocious puberty and in patients with isolated hypogonadotropic hypogonadism. Plasma dehydroepiandrosterone, dehydroepiandrosterone sulfate, androstenedione, and cortisol were measured basally and during an infusion of ACTH in 50 children with precocious puberty, 5 patients with isolated hypogonadotropic hypogonadism, 7 preadrenarchal children with constitutional short stature, 44 normal pubertal children, and 40 normal adults. Children with precocious puberty did not have a corresponding advance in the timing of adrenarche. Their basal and ACTH-stimulated adrenal androgen levels were markedly lower than those of normal children matched for pubertal stage (P less than 0.05) and were only slightly greater than those reported for normal children of the same age. Similarly, patients with isolated hypogonadotropic hypogonadism and delayed puberty had no corresponding delay of adrenarche. Their adrenal androgen levels were appropriate for chronological age. Thus, these data provide further support for the hypothesis that adrenarche and gonadarche are independent maturational events controlled by separate mechanisms.