Serum cortisol and cortisone levels in newborns with congenital adrenal hyperplasia before the start of therapy.

Sodium loss in infants with salt wasting (SW) congenital adrenal hyperplasia (CAH) does usually not occur within the first week of life. We hypothesized that sufficient mineralocorticoid activity might by temporarily maintained by still appropriate concentrations of cortisol. Plasma samples were obtained from 15 infants with SW-CAH before the onset of sodium loss, 17 patients with simple virilizing (SV)-CAH and 28 healthy infants under 14 days of age. Plasma aldosterone concentrations were significantly lower in SW-CAH infants than in SV-CAH patients and in healthy neonates. Plasma cortisol levels and cortisol/cortisone (F/E) ratios in SW-CAH patients were almost the same as in the SV-CAH and control group. While declining plasma aldosterone levels precede the onset of SW in CAH patients, plasma cortisol concentrations are kept normal in SW-CAH infants, temporarily maintaining sufficient mineralocorticoid activity.

Evidence for change of 11beta-hydroxysteroid dehydrogenase activity during infancy and childhood.

The conversion of cortisol (F) to cortisone (E) is catalyzed by 11beta-hydroxysteroid dehydrogenase type 2. The present study was designed to investigate the changes of F and E plasma concentration as an indirect measurement of 11beta-hydroxysteroid dehydrogenase activity in infancy and childhood. Plasma samples were obtained from 262 healthy children and adolescents aged 1 d to 18 y. Plasma F and E were measured, using specific radioimmunoassays after extraction and automated Sephadex LH 20 chromatography. The F/E ratio was calculated to assess 11beta-hydroxysteroid dehydrogenase activity. During the first year of life, plasma F levels rose significantly (r(2) = 0,24; p = 0.01), and thereafter no further increase was seen until adulthood (r(2) = 0.01; p = 0.86). In contrast, plasma E significantly decreased during the first year of life (r(2) = -0.35; p<0.001) and stayed unchanged thereafter (r(2) = 0.02; p = 0.81). As a consequence, the F/E ratio rose significantly during the first year (r(2) = 0.67; p<0.001) but did not change afterward (r(2) = 0.001; p = 0.99). During the first year of life, there is a change from the predominance of E, with low mineralocorticoid receptor affinity, to F, with high mineralocorticoid receptor affinity. This shift corresponds to the declining plasma concentrations of aldosterone during infancy. The changes may indicate a not yet recognized, significant change of 11beta-hydroxysteroid dehydrogenase isoenzyme activity or alterations in the secretion of F and E, which may be of relevance for the development of arterial blood pressure in infancy.