Urinary pregnanetriol-3-glucuronide in children: age-related change and application to the management of 21-hydroxylase deficiency.

Urinary concentrations of pregnanetriol-3-glucuronide (PT-3-G) were determined in 485 normal Japanese subjects (277 males and 208 females), aged 5 days to 20 years, using an enzyme-linked immunosorbent assay (ELISA). The usefulness of urinary PT-3-G concentrations before giving the morning dose of medications in monitoring the adequacy of glucocorticoid treatment was assessed in eight patients with 21-hydroxylase deficiency (21-OHD). The ratio of PT-3-G to excreted creatinine (PT-3-G/Cre ratio) increased significantly during the first month and did not change from age 1 month to 1 year of life. The ratio decreased to a nadir at age 3 or 4 years followed by continuous, significant increase until late adolescence. In the subjects treated with corticosteroids for 21-OHD, PT-3-G/Cre ratios at the 50th percentile or below suggested a risk of excessive treatment, as judged by the patients' growth. Measurement of the PT-3-G/Cre ratio enabled recognition of corticosteroid overtreatment, which was not demonstrated by determining the serum concentrations of 17 alpha-hydroxyprogesterone (17-OHP). On the other hand, ratios at the upper 95-99% tolerance limits seemed to be required for optimal control. The present study revealed the normal age-related changes in urinary excretion of PT-3-G and showed it to be a reliable marker for evaluating glucocorticoid treatment in young children with 21-OHD.