It has long been observed that the adrenal cortex of the newborn child differs morphologically from that of the older child or the adult. With the advent of corticotropin (ACTH) and more precise analytical procedures, studies were initiated to determine whether the adrenal cortex of the newborn infant responds as actively to stress as does the older child or the adult.
Klein and Hanson1 reported less response to corticotropin in infants during the first week of life than in infants over a week old, as determined by the eosinophile response. However, Bergstrand and co-workers2 have challanged the validity of the eosinophile measurements as evidence of adrenocortical activity. Read and co-workers3 administered corticotropin to infants and determined adrenocortical activity by measuring the urinary output of 17-ketosteroids and corticosteroids. They observed a response to corticotropin in the newborn infant when sufficient hormone was injected. However, only 10 infants were