(Chest. 2003;123:405S.)
© 2003
American College of Chest Physicians
Hypothalamic-Pituitary-Adrenal Axis Dysfunction During Sleep in Nocturnal Asthma*
E. Rand Sutherland, MD, FCCP;
Monica Kraft, MD, FCCP;
M.D. Rex, BS;
Misoo C. Ellison, PhD and
Richard J. Martin, MD, FCCP
* From the National Jewish Medical and Research Center, Denver, CO.
Correspondence to: R.J. Martin, MD, FCCP, National Jewish Medical and Research Center, 1400 Jackson St, Denver, CO 80206; e-mail: martinr{at}njc.org
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Introduction
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Patients with nocturnal asthma (NA) have increased airway inflammation at night, a phenomenon not seen in patients with non-NA (NNA). We hypothesized that alterations in hypothalamic-pituitary-adrenal axis function may be of importance in the pathogenesis of NA.
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Materials and Methods
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Subjects with NA (four subjects), NNA (six subjects), and healthy control subjects (NL; six subjects) maintained a mini-constant-sleep-wake routine for 8 days. On day 8, serum samples were drawn every 2 h over a 24-h period (12 samples per subject) and were analyzed for circadian differences in corticotropin (ACTH) and cortisol levels. Between-group comparisons were made at each time point during the hours of sleep (ie, 10:00 PM to 6:00 AM) using repeated-measures analysis of variance.
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Results
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During sleep, there was a linear increase in both ACTH and cortisol levels in all three groups (p < 0.004).
ACTH
Mean (± SEM) ACTH levels in NA subjects were the highest at 4:00 AM (28.5 ± 3.9 pg/mL). Mean ACTH levels at 4:00 AM in NNA subjects (14.3 ± 3.2 pg/mL; p = 0.01, NA vs NNA group) and NL subjects, (16.0 ± 3.8 pg/mL; p = 0.03, NA vs NL) were similar, lower than NA subjects. ACTH levels of NNA subjects did not differ from those of NLs (p = 0.74).
Cortisol
Although NA subjects had the highest mean cortisol levels at 4:00 AM (17.1 ± 3.7 µg/dL), they were not significantly greater than the levels of NNA subjects (13.3 ± 2.2 µg/dL; p = 0.31). The cortisol levels of NA subjects were higher than those of NLs (7.4 ± 2.5 µg/dL; p = 0.01), but those of NNA subjects were not (p = 0.08).
ACTH/Cortisol Correlation
Within-group correlations between ACTH and cortisol levels were (in ascending order) as follows: NA group, r = 0.71 and p = 0.0005; NNA group, r = 0.74 and p = 0.0001; and NL group, r = 0.82 and p = 0.0001.
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Conclusions
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Although subjects with NA demonstrate significantly increased ACTH levels at night, these were not accompanied by a commensurate cortisol response. The adrenal response to ACTH may be blunted in NA subjects, permitting increased airway inflammation in these subjects.
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Footnotes
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Abbreviations: ACTH = corticotropin; NA = nocturnal asthma; NL = control subject; NNA = nonnocturnal asthma
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Introduction
Materials and Methods
