Urinary excretion of 19-norandrosterone of endogenous origin in man: quantitative analysis by gas chromatography-mass spectrometry

J Chromatogr B Biomed Sci Appl. 1999 Jan 22;721(2):301-7. doi: 10.1016/s0378-4347(98)00480-0.

Abstract

A GC-MS method, using deuterium-labelled 19-noretiocholanolone as internal standard and following an extensive LC purification prior to selected ion monitoring of the bis(trimethylsilyl) ethers at ion masses m/z 405, 419, 420 and 421, allowed the quantitation of subnanogram amounts of 19-norandrosterone present in 10-ml urine samples at m/z 405. Thirty healthy men, free of anabolic androgen supply, delivered 24-h urine collections in 4 timed fractions. Accuracy was proven by the equation, relating added (0.05-1 ng/ml) to measured analyte, which had a slope not significantly different from 1. Precision (RSD) was 4% at a concentration of 0.4 ng/ml, and 14% at 0.04 ng/ml. Analytical recovery was 82%. The limit of quantitation was 0.02 ng/ml. The excretion ranges were 0.03-0.25 microg/24 h or 0.01-0.32 ng/ml in nonfractionated 24-h urine. Taking into account inter-individual variability and log-normal distribution, a threshold of 19-norandrosterone endogenous concentration of 2 ng/ml, calculated as the geometric mean plus 4 SD, was established. This value corresponds to the decision limit advised by sport authorities for declaring positive (anabolic) doping with nandrolone.

Publication types

  • Clinical Trial

MeSH terms

  • Adolescent
  • Adult
  • Chromatography, Ion Exchange
  • Chromatography, Liquid
  • Circadian Rhythm
  • Doping in Sports*
  • Estranes / urine*
  • Gas Chromatography-Mass Spectrometry
  • Humans
  • Male
  • Middle Aged
  • Reference Values
  • Substance Abuse Detection / methods*

Substances

  • Estranes
  • 19-norandrosterone