LC-MS based simultaneous profiling of adrenal hormones of steroids, catecholamines, and metanephrines

Abstract

Metabolic changes in adrenocortical steroids and medullary catecholamines characterize adrenal tumors, but they are measured using different analytical protocols. To increase bioanalytical validity while maintaining sample homogeneity, LC-MS-based profiling of 29 cortical steroids and 6 medullary amines, including catecholamines and metanephrines, in a single run was developed. Alkyloxycarbonylation with isobutyl chloroformate was employed together with our comprehensive steroid assay, and all adrenal hormones were separated on a reversed-phase C18 column (50 × 2.1 mm, 1.9 μm) at a flow rate of 0.3 ml/min. The lower limits of quantification for all analytes ranged from 0.1 to 2.0 ng/ml, with extraction recoveries of 58.5%–109.5%, while the imprecision and accuracy were 1.6%–14.8% and 89.2%–114.9%, respectively. The validated LC-MS assay was applied to serum samples obtained from 60 patients with adrenal Cushing syndrome, primary aldosteronism, and pheochromocytoma/paraganglioma (PPGL). In addition to the characteristic metabolic changes in glucocorticoids, mineralocorticoids, catecholamines, and metanephrine, the molecular ratios of dehydroepiandrosterone sulfate and 20α-dihydrocortisol indicated Cushing syndrome and primary aldosteronism (P < 0.01 for all compounds), respectively. Moreover, the interactive molecular ratios of 11-deoxycortisol with normetanephrine, metanephrine, norepinephrine, and epinephrine (P < 0.01 all compounds) were proposed to characterize the metabolic features of PPGL. Novel LC-MS-based quantitative profiling of steroids, catecholamines, and metanephrines in human serum was successfully established and characterized metabolic features of individual adrenal tumors that could be used for clinical purposes.

Keywords

• adrenal tumor
• chemical derivatization
• mass spectrometry
• adrenal cortex
• adrenal medullar