Cortisol production rate measurement by stable isotope dilution using gas chromatography-negative ion chemical ionization mass spectrometry

David D. Brandon, Lorne M. Isabelle, Mary Samuels, John Kendall, Donald (Lynn) Loriaux

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Presented here is a stable isotope dilution technique for determining cortisol production rate (CPR). The method involves extraction and derivatization of cortisol isoforms from serum (0.5 ml), separation of derivatives by gas chromatography, and detection by using negative ion chemical ionization mass spectrometry. This method provides 50-100-fold greater sensitivity than positive ion mass spectrometry and allows for estimations of cortisol production rate with the use of small amounts of pooled serum, even in the presence of high concentrations of lipophilic contaminants. The area under the curve for the total selected ion chromatogram of fluoroacyl derivatives of cortisol (d0, m/z 782) and deuterated cortisol (d3, m/z 785) were used to determine the isotopic dilution ratio in three types of samples: 1) standards: d0/d3 ratios ranging from 1 to 8%; 2) controls: d3-cortisol added to serum with known cortisol concentration; 3) subjects: 24-h pooled serum samples (q 30 min over 24 h) from healthy children (male 10-13 years; female 7-11 years) receiving continuous infusions of d3-cortisol at 2-4% of their estimated CPR. Recovery after the solid phase extraction and derivatization process was >90%, as determined by thin-layer chromatography. Expected versus measured ratios for d3/d0 in standards and serum controls were highly correlated (r2(standard) = 0.99; r2(control) = 0.99) over a wide range of d3-cortisol enrichment (1.0-10.0%). Mean 24-h CPRs were 4.8 ± 0.6 mg/m2/24 h (mean ± SEM, n = 7) in male children and 4.4 ± 0.5 mg/m2/24 h in female children (n = 4). These CPR values are lower than those derived by radio tracer methods, but are in agreement with previous isotopic dilution studies. This technique is an important tool for assessing CPRs in a wide range of disease states affecting cortisol production.

Original languageEnglish (US)
Pages (from-to)372-378
Number of pages7
JournalSteroids
Volume64
Issue number6
DOIs
StatePublished - Jun 1999

Fingerprint

Isotopes
Gas chromatography
Gas Chromatography
Dilution
Ionization
Mass spectrometry
Hydrocortisone
Mass Spectrometry
Negative ions
Ions
Serum
Cardiopulmonary Resuscitation
Derivatives
Indicator Dilution Techniques
Thin layer chromatography
Solid Phase Extraction
Thin Layer Chromatography
Radio
Area Under Curve
Protein Isoforms

Keywords

  • Cortisol production rate
  • Mass spectrometry

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology
  • Molecular Biology

Cite this

Cortisol production rate measurement by stable isotope dilution using gas chromatography-negative ion chemical ionization mass spectrometry. / Brandon, David D.; Isabelle, Lorne M.; Samuels, Mary; Kendall, John; Loriaux, Donald (Lynn).

In: Steroids, Vol. 64, No. 6, 06.1999, p. 372-378.

Research output: Contribution to journalArticle

@article{00c70bdf18354881ad10c96be31300ae,
title = "Cortisol production rate measurement by stable isotope dilution using gas chromatography-negative ion chemical ionization mass spectrometry",
abstract = "Presented here is a stable isotope dilution technique for determining cortisol production rate (CPR). The method involves extraction and derivatization of cortisol isoforms from serum (0.5 ml), separation of derivatives by gas chromatography, and detection by using negative ion chemical ionization mass spectrometry. This method provides 50-100-fold greater sensitivity than positive ion mass spectrometry and allows for estimations of cortisol production rate with the use of small amounts of pooled serum, even in the presence of high concentrations of lipophilic contaminants. The area under the curve for the total selected ion chromatogram of fluoroacyl derivatives of cortisol (d0, m/z 782) and deuterated cortisol (d3, m/z 785) were used to determine the isotopic dilution ratio in three types of samples: 1) standards: d0/d3 ratios ranging from 1 to 8{\%}; 2) controls: d3-cortisol added to serum with known cortisol concentration; 3) subjects: 24-h pooled serum samples (q 30 min over 24 h) from healthy children (male 10-13 years; female 7-11 years) receiving continuous infusions of d3-cortisol at 2-4{\%} of their estimated CPR. Recovery after the solid phase extraction and derivatization process was >90{\%}, as determined by thin-layer chromatography. Expected versus measured ratios for d3/d0 in standards and serum controls were highly correlated (r2(standard) = 0.99; r2(control) = 0.99) over a wide range of d3-cortisol enrichment (1.0-10.0{\%}). Mean 24-h CPRs were 4.8 ± 0.6 mg/m2/24 h (mean ± SEM, n = 7) in male children and 4.4 ± 0.5 mg/m2/24 h in female children (n = 4). These CPR values are lower than those derived by radio tracer methods, but are in agreement with previous isotopic dilution studies. This technique is an important tool for assessing CPRs in a wide range of disease states affecting cortisol production.",
keywords = "Cortisol production rate, Mass spectrometry",
author = "Brandon, {David D.} and Isabelle, {Lorne M.} and Mary Samuels and John Kendall and Loriaux, {Donald (Lynn)}",
year = "1999",
month = "6",
doi = "10.1016/S0039-128X(98)00112-3",
language = "English (US)",
volume = "64",
pages = "372--378",
journal = "Steroids",
issn = "0039-128X",
publisher = "Elsevier Inc.",
number = "6",

}

TY - JOUR

T1 - Cortisol production rate measurement by stable isotope dilution using gas chromatography-negative ion chemical ionization mass spectrometry

AU - Brandon, David D.

AU - Isabelle, Lorne M.

AU - Samuels, Mary

AU - Kendall, John

AU - Loriaux, Donald (Lynn)

PY - 1999/6

Y1 - 1999/6

N2 - Presented here is a stable isotope dilution technique for determining cortisol production rate (CPR). The method involves extraction and derivatization of cortisol isoforms from serum (0.5 ml), separation of derivatives by gas chromatography, and detection by using negative ion chemical ionization mass spectrometry. This method provides 50-100-fold greater sensitivity than positive ion mass spectrometry and allows for estimations of cortisol production rate with the use of small amounts of pooled serum, even in the presence of high concentrations of lipophilic contaminants. The area under the curve for the total selected ion chromatogram of fluoroacyl derivatives of cortisol (d0, m/z 782) and deuterated cortisol (d3, m/z 785) were used to determine the isotopic dilution ratio in three types of samples: 1) standards: d0/d3 ratios ranging from 1 to 8%; 2) controls: d3-cortisol added to serum with known cortisol concentration; 3) subjects: 24-h pooled serum samples (q 30 min over 24 h) from healthy children (male 10-13 years; female 7-11 years) receiving continuous infusions of d3-cortisol at 2-4% of their estimated CPR. Recovery after the solid phase extraction and derivatization process was >90%, as determined by thin-layer chromatography. Expected versus measured ratios for d3/d0 in standards and serum controls were highly correlated (r2(standard) = 0.99; r2(control) = 0.99) over a wide range of d3-cortisol enrichment (1.0-10.0%). Mean 24-h CPRs were 4.8 ± 0.6 mg/m2/24 h (mean ± SEM, n = 7) in male children and 4.4 ± 0.5 mg/m2/24 h in female children (n = 4). These CPR values are lower than those derived by radio tracer methods, but are in agreement with previous isotopic dilution studies. This technique is an important tool for assessing CPRs in a wide range of disease states affecting cortisol production.

AB - Presented here is a stable isotope dilution technique for determining cortisol production rate (CPR). The method involves extraction and derivatization of cortisol isoforms from serum (0.5 ml), separation of derivatives by gas chromatography, and detection by using negative ion chemical ionization mass spectrometry. This method provides 50-100-fold greater sensitivity than positive ion mass spectrometry and allows for estimations of cortisol production rate with the use of small amounts of pooled serum, even in the presence of high concentrations of lipophilic contaminants. The area under the curve for the total selected ion chromatogram of fluoroacyl derivatives of cortisol (d0, m/z 782) and deuterated cortisol (d3, m/z 785) were used to determine the isotopic dilution ratio in three types of samples: 1) standards: d0/d3 ratios ranging from 1 to 8%; 2) controls: d3-cortisol added to serum with known cortisol concentration; 3) subjects: 24-h pooled serum samples (q 30 min over 24 h) from healthy children (male 10-13 years; female 7-11 years) receiving continuous infusions of d3-cortisol at 2-4% of their estimated CPR. Recovery after the solid phase extraction and derivatization process was >90%, as determined by thin-layer chromatography. Expected versus measured ratios for d3/d0 in standards and serum controls were highly correlated (r2(standard) = 0.99; r2(control) = 0.99) over a wide range of d3-cortisol enrichment (1.0-10.0%). Mean 24-h CPRs were 4.8 ± 0.6 mg/m2/24 h (mean ± SEM, n = 7) in male children and 4.4 ± 0.5 mg/m2/24 h in female children (n = 4). These CPR values are lower than those derived by radio tracer methods, but are in agreement with previous isotopic dilution studies. This technique is an important tool for assessing CPRs in a wide range of disease states affecting cortisol production.

KW - Cortisol production rate

KW - Mass spectrometry

UR - http://www.scopus.com/inward/record.url?scp=0032798797&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032798797&partnerID=8YFLogxK

U2 - 10.1016/S0039-128X(98)00112-3

DO - 10.1016/S0039-128X(98)00112-3

M3 - Article

C2 - 10433173

AN - SCOPUS:0032798797

VL - 64

SP - 372

EP - 378

JO - Steroids

JF - Steroids

SN - 0039-128X

IS - 6

ER -