Unconjugated Dehydroepiandrosterone Plasma Levels in Normal Subjects from Birth to Adolescence in Human: The Use of a Sensitive Radioimmunoassay1

Abstract

A specific and sensitive radioimmunoassay for measuring unconjugated plasma dehydroepiandrosterone (DHA) has been developed and the results expressed in ng/100 ml. Mean values +/-1 SD were in mixed cord blood 593.3 +/- 186.5 in 21 females and 712.7 +/- 190.9 in 18 males. During the first day of life the peripheral plasma concentration of DHA was 917.6 +/- 317.8 in 22 female and 922.65 +/- 290 in 17 male neonates. During the first month of age, DHA levels decreased significantly and then more progressively throughout the first year of life. Mean levels observed between the first and 6th month of life were 147.1 +/- 53.6 in 15 girls and 151.6 +/- 62.7 in 28 boys. Between 6 and 12 months of age mean DHA levels were 90.9 +/- 43.3 and 68.14 +/- 30.9 in 11 girls and 24 boys, respectively. In 250 normal children, plasma DHA levels were very low between 1 to 6 years of age, but rising progressively thereafter without any sex difference long before any clinical sign of puberty. A circadian rhythm parallel to that of cortisol was observed as early as 5 years of age. Acute and chronic stimulation of ACTH confirmed the adrenal origin of DHA, while the results of hCG stimulation test and fluoxymesterone suppression test assessed the testicular participation to the DHA production.