ADRENOCORTICAL STEROID METABOLISM IN NEWBORN INFANTS. I. URINARY EXCRETION OF FREE AND CONJUGATED 17-HYDROXYCORTICOSTEROIDS IN NORMAL FULL-TERM INFANTS*

Abstract

The urinary Porter-Silber chromogens of 27 normal full-term newborn infants were studied after extraction with methylene dichloride before and after hydrolysis with beta-glucuronidase. The values for total steroid were generally lower than would be predicted on the basis of small body size alone. The free steroid fraction accounted for a higher percentage of the total steroids than is commonly found in adult man. Unlike the urinary pattern in the adult, unmetabolized cortisol was not the major steroid component of the free fraction. Excretion values showed a trend toward increasing with each day of life. This trend was most evident for the steroids released during incubation with beta-glucuron-idase. Because of the great variability in steroid excretion and the small size of the sample, no determination of limits for the range of urinary 17-hydroxycorticosteroid excretion nor interpretation of the state of adrenal function in the normal infants studied seemed justified.