Circadian cortisol secretion and circadian adrenal responses to ACTH are maintained in dexamethasone suppressed capuchin monkeys (Cebus apella)

Authors

  • Claudia Torres-Farfan,

    1. Departamento de Ciencias Fisiológicas, Pontificia Universidad Católica de Chile Santiago, Chile
    2. Programa de Fisiopatología, ICBM, Facultad de Medicina, Universidad de Chile Santiago, Chile
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  • Francisco J. Valenzuela,

    1. Programa de Fisiopatología, ICBM, Facultad de Medicina, Universidad de Chile Santiago, Chile
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  • Renato Ebensperger,

    1. Departamento de Ciencias Fisiológicas, Pontificia Universidad Católica de Chile Santiago, Chile
    2. Programa de Fisiopatología, ICBM, Facultad de Medicina, Universidad de Chile Santiago, Chile
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  • Natalia Méndez,

    1. Departamento de Ciencias Fisiológicas, Pontificia Universidad Católica de Chile Santiago, Chile
    2. Programa de Fisiopatología, ICBM, Facultad de Medicina, Universidad de Chile Santiago, Chile
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  • Carmen Campino,

    1. Facultad de Medicina, Departamento de Endocrinologia, Pontificia Universidad católica de Chile, Santiago, Chile
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  • Hans G. Richter,

    1. Instituto de Histología y patología Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
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  • Guillermo J. Valenzuela,

    1. Department of Women's Health, Arrowhead Regional Medical Center, Colton, California
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  • María Serón-Ferré

    Corresponding author
    1. Programa de Fisiopatología, ICBM, Facultad de Medicina, Universidad de Chile Santiago, Chile
    2. Universidad de Tarapacá and CIHDE, Arica, Chile
    • Programa de Fisiopatología, ICBM, Facultad de Medicina, Universidad de Chile, Casilla 16038 correo 9, 3419147
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Abstract

We tested the hypothesis that the capuchin monkey adrenal (Cebus apella) gland has oscillatory properties that are independent of adrenocorticotropic hormone (ACTH) by exploring under ACTH suppression by dexamethasone: (i) maintenance of a circadian rhythm of plasma cortisol and (ii) clock time dependency of plasma cortisol response to exogenous ACTH. The capuchin monkey had a clear ACTH and plasma cortisol rhythm. Dexamethasone treatment resulted in low non-rhythmic ACTH levels and decreased cortisol to 1/10 of control values; nevertheless, the circadian rhythm of plasma cortisol persisted. We found that cortisol response to exogenous ACTH was clock time-dependent. The maximal response to ACTH occurred at the acrophase of the cortisol rhythm (0800 h). These results suggest that the capuchin monkey adrenal cortex may possess intrinsic oscillatory properties that participate in the circadian rhythm of adrenal cortisol secretion and in the circadian cortisol response to ACTH. Am. J. Primatol. 70:93–100, 2008. © 2007 Wiley-Liss, Inc.

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