[The simultaneous measurement of cortisol and cortisone in the plasma and tissues by high-resolution liquid...

Measurement of cortisol (F) and cortisone (E) are important to study cortisol metabolism during gestation or in hypertensive patients. We developed a method for simultaneous measurement of F and E based on plasma extraction by dichloromethane, separation by high resolution chromatography and detection at 254 nm. Good correlation between this method and RIA was obtained in measurements of maternal plasma cortisol (r = 0.77). Retention times for F and E were 25 +/- 0.6 and 20 +/- 0.4 min respectively. F and E recovery was 73% (interassay coefficient 7.1%). Conversion of F to E in controls and in human placenta, but not in pseudohyperaldosteronism, is detected by the method. F values in maternal blood (269 +/- 12 ng/ml), umbilical artery (61 +/- 5), umbilical vein (44 +/- 3) and E values in maternal blood (40 +/- 1), umbilical artery (57 +/- 4) and umbilical vein (61 +/- 4), were similar to those reported in the literature. Thus, HPLC is a simple, reliable and reproducible method for measurement of cortisol and cortisone.