Adrenal androgen response to metyrapone, adrenocorticotropin, and corticotropin-releasing hormone stimulation in children with hypopituitarism

We determined the adrenal steroid responses to metyrapone, ACTH, and CRH in 12 ACTH-intact and 5 ACTHdeficient hypopituitary children to determine the mechanisms that control adrenal androgen secretion. Serum adrenal androgen concentrations [dehydroepiandrosterone (DHEA) and Δ⁴-androstenedione (Δ⁴-A)] rose in response to oral administration of metyrapone (450 mg/m²dose, every h for 7 doses) in ACTHintact hypopituitary children with multiple or isolated pituitary hormone deficiencies [mean postmaryrapone level: DHEA, 225 ng/dL (range, 27-566); Δ⁴-A, 313 ng/dL (range, 105-651)], except in 2 young children in whom DHEA did not rise. These adrenal androgens did not rise in all ACTH-deficient hypopituitary children [mean postmetyrapone level: DHEA, 11.0 ng/dL range, 3-16); Δ⁴-A, 6.2 ng/dL (range, 3-10)]. The increases in both serum cortisol and adrenal androgens, including DHEA sulfate, in response to short term ACTH infusion (40 U in 6 h) in ACTH-intact hypopituitary children were normal or above normal, while these steroid responses were significantly (P < 0.05-0.01) lower in ACTH-deficient hypopituitary children compared to normal values. However, prolonged administration of ACTH (40 U/day, or im) for 6 days to 2 ACTH-deficient hypopituitary children resulted in normal DHEA responses to the 6-h ACTH stimulation test (DHEA levels after the first test, 14 and 30 ng/dL, after priming, 80 and 50 ng/dL). Furthermore, CRH administration to 4 ACTH-deficient patients caused a rise in serum DHEA and cortisol in patients with a normal ACTH response, while those with a poor ACTH response had a lesser rise in DHEA and cortisol. These data suggest that ACTH is the major tropic hormone for adrenal androgen secretion.