Hypothalamo-pituitary-adrenal axis after a single epidural triamcinolone injection
To quantify adrenocorticotropin and cortisol secretion after epidural glucocorticoid injection.
Eight men (ages 25–63 year) were studied at baseline, 1, 4, and 12 weeks after triamcinolone (80 mg) injection epidurally. Adrenocorticotropin (pg/mL) and cortisol (µg/dL) were measured every 10 min for 4 h, and after Corticotropin-releasing hormone (CRH) (1 µg/kg) injection.
Epidural triamcinolone markedly suppressed: (1) pre-CRH injection ACTH (from 18 ± 3.1 to 4.8 ± 0.4: P < 0.01) and cortisol (from 12.2 ± 1.6 to 1.6 ± 0.3: P < 0.0001) at week 1, with recovery at 4 weeks, and (2) CRH-stimulated 3-h summed ACTH (from 633 ± 116 to 129 ± 10 pg/mL, P < 0.0001), and 3-h summed cortisol at week 1 (from 385 ± 29 to 56 ± 22 µg/dL, P < 0.0001) and 4 weeks (284 ± 53; P < 0.01). Serum cortisol was <18 µg/dL in eight of eight men at 4 weeks, and six of eight men at week 12. Urinary-free cortisol (µg/24 h) remained low at week 12: baseline (60 ± 6.5); week 1 (9.0 ± 1.3, P < 0.01); week 4 (36 ± 8.6) and week 12 (38 ± 4.1). Urinary cortisol/cortisone ratios rose at week 4 only. Serum triamcinolone peaked at week 1 (16/16 samples), declining at week 4 (13/16 samples) and week 12 (6/16 samples).
Relatively small group.
Epidural triamcinolone suppresses unstimulated and CRH-stimulated ACTH and cortisol secretion for 1–4 weeks but urinary free cortisol ≥12 weeks. Suppression of ACTH and cortisol after glucocorticoid treatment is thus complex.
KeywordsGlucocorticoid ACTH Cortisol Human Inhibition
analysis of variance
Central nervous system
Structure equation of modeling
We thank Jill Smith for support of manuscript preparation and the Mayo Immunochemical Laboratory for assistance with mass spectrometry (RJS). All authors have had access to the data and a role in writing the manuscript.
This study was funded in part by the National Institutes of Health in Bethesda, MD [R01 DK073148 (JDV)], and the Salem Research Institute of the Salem VA Medical Center (AI). The Mayo Immunochemical Laboratory provided assistance with mass spectrometry (RJS). Supported in part via R01 DK073148 (JDV) from the National Institutes of Health (Bethesda, MD), and the Salem Research Institute of the Salem VA Medical Center (AI). Contents are solely the responsibility of the authors and do not necessarily represent the official views of any federal institution.
Conception and design of research (A.I., J.D.V., D.G.); performed experiments (A.I., D.G.); analyzed data (J.D.V.); interpreted results of experiments (A.I., J.D.V.); drafted manuscript (A.I., J.D.V.); prepared figures (A.I., J.D.V.); edited and revised manuscript (A.I., J.D.V.); approved final version of manuscript (A.I., D.G., R.S., J.D.V.).
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no competing interests.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors.
Informed consent was obtained from all individual participants included in the study.
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