title: Inborn errors of steroid biosynthesis: detection by a new mass-spectrometric method.
abstract: A new mass-spectrometric technique relies on ionization during bombardment of the analyte (dissolved in a liquid matrix, usually glycerol) by an atom beam (e.g., Ar0, Xe0). This technique, termed "fast atom bombardment," is particularly useful in the characterization of polar charged molecules. A neutral beam is not essential, and a primary beam of cesium ions has been successfully used to produce spectra equivalent to those obtained by fast atom bombardment. In this communication I report data on the use of both ion and atom primary beams for producing secondary-ion mass spectra of conjugated steroids. In negative-ion spectra produced for steroid glucuronides and sulfates, the ion [M - H]- is invariably the major high-mass peak, and the lack of substantial fragmentation allows assay of relatively complex mixtures if the analytes differ in mass. I describe here the use of secondary-ion mass spectrometry for distinguishing, by urinary steroid analysis, patients with the four enzyme defects that can affect cortisol synthesis: defects in 17 alpha-hydroxylase, 3 beta-hydroxysteroid dehydrogenase/isomerase, 21-hydroxylase, and 11 beta-hydroxylase.
mesh_terms: D005965:Glucuronates / Q000652:urine; D006801:Humans; D006854:Hydrocortisone / Q000096:biosynthesis* / Q000652:urine; D013058:Mass Spectrometry / Q000379:methods; D008661:Metabolism, Inborn Errors / Q000378:metabolism* / Q000652:urine; D006899:Mixed Function Oxygenases / Q000378:metabolism; D011375:Progesterone Reductase / Q000378:metabolism; D013254:Steroid 17-alpha-Hydroxylase / Q000378:metabolism; D013431:Sulfates / Q000652:urine
chemical_list: D005965:Glucuronates; D013431:Sulfates; D006899:Mixed Function Oxygenases; D011375:Progesterone Reductase; D013254:Steroid 17-alpha-Hydroxylase; D006854:Hydrocortisone