Abstract
The author intended to investigate how the adrenal cortex of healthy infants and children respond to the successive administration of adrenocorticotropin (ACTH), especially according to their ages. The subjects consisted of 22 healthy infants and children, aged from 2 months to less than 15 years. Daily doses of 20 units of ACTH-Z were given intramuscularly for 5 successive days. The urinary total 17-hydroxycorticosteroids (17-OHCS) excretion was determined by the modified Porter-Silber method and the results were evaluated by three age goups, divided into infants (from 2 months to 1 year of age), young children (from 2 years to 6 years of age) and older children (from 7 years to 14 years of age).
1) During the successive administration of ACTH, the urinary total 17-OHCS excretion increased significantly in all subjects, the maximum values during the observation (mean values, confidence limits) were 12.74±6.07 mg./day in infants, 13.05±4.45 mg./ day in young children, and 14.61±2.97 mg/day in older children, respectively. No significant differences due to ages were found among these absolute values.
2) However, when these absolute values were calculated by the body surface area, the maximum values showed 44.42-±16.46 mg./m2/day in infants, 21.42±6.93 mg./m2/ day in young children, and 16.20±4.22 mg./m2/day in older children, respectively. The maximum value obtained in infants was significantly higher than those obtained in the other two groups of children. Furthermore, the values of increased excretion during ACTH administration as compared with those of basal excretion were also higher in infants.
3) The values in young and older children reached the maximum often on the 3rd day of the administration without a remarkable increase afterwards. However, they in-creased in most cases of infants continuously during the whole period of the observation and reached the maximum just on the 5th day of the administration.
4) These results are considered to be of significance in order to recognize adrenocortical reserve, especially its maximal response, in infancy and childhood. It is concluded, that the adrenocortical reserve in infants is not inferior, as compared with those of young and older children, and it seems, furthermore, to be possible even to interpret that this reserve power may be comparatively superior in infants.
