USE OF 13C-CORTISOL TO DETERMINE THE CORTISOL PRODUCTION RATE (CPR) IN CONGENITAL ADRENAL HYPERPLASIA DUE TO 17-ALPHA-HYDROXYLASE DEFICIENCY

Abstract

1, 2, 3, 4-13C cortisol(13C-F) was used to measure the CPR in two sisters(karyotype 46, XX)of 11(I) and 3(II) yrs of age with 17α-hydroxylase deficiency. The disease was diagnosed on hyper tension, low plasma cone, of 17β-estradiol, cortisol, PRA and aldosterone and high conc, of progesterone and in patient I of ACTH, FSH and LH. Both children excreted in the urine high amounts of tetra-and hexahydro-metabolites of corticosterone and deoxycorticosterone and (very) low amounts of metabolites of cortisol (F), androstenedione and testosterone.After the i.v. dosage of 60 and 2.4 μg to patient I and II, urine was collected for 3 days. After extraction, hydrolysis and HPLC Chromatography the metabolites of F were oxidised to 11-oxoetiocholanolone (11-OET) and -androsterone. The 13C-enrichments in the methoxime-tert.butyldimethylsily ethers were measured by gas Chromatography mass fragmentography at the leading ions m/z 348 (13C4) and 344 (12C). Calibration standards were prepared from mixtures of 13C-F and F, which were oxidised to cortisone (E), reduced to tetrahydrocortisone (THE) by Cl.paraputrificum and oxidised to 11-OET. The CPR (mg/day) was for I:0.28±0.003 (THE) and 0.19±0.007 (α+βcortolone) and for II:0.022±0.003 (THE). Owing to the very low amounts of cortisol metabolites the CPR determinations would not have been possible if tritiated cortisol was used. Financial support was obtained from the Netherlands Organisation for the Advancement of Pure Research (ZWO).