Glucocorticoid regulation of Nramp1 in host resistance to mycobacteria

  • David H. Brown
  • Bruce S. Zwilling

Abstract

The ability of glucocorticoid hormones to effectively modulate an immune response has been widely studied. Glucocorticoid production and release from the adrenal cortex is stimulated primarily by adrenocorticotrophin (ACTH), which in turn, is controlled by Corticotrophin-releasing hormone (CRH) derived from the hypothalamus [1]. Circadian rhythms or “episodic” increases and decreases occur during each day. Stress overrides feedback regulation of glucocorticoid levels resulting in elevated levels of glucocorticoids. Alterations in corticosterone levels results in either an enhancement or suppression of defence mechanisms. Glucocorticoids, which freely penetrate the cell, bind to their cytoplasmic receptor [2]. The hormone-receptor complex translocates to the nucleus and binds to regulatory elements associated with certain genes (glucocorticoid response elements), which can activate or inhibit transcription of those genes. Glucocorticoids probably have primary and secondary cell targets. Primary targets are affected directly by glucocorticoids through the binding of the hormone to its receptor, whereas secondary target cells are affected by mediators (cytokines) produced by primary target cells which are regulated, themselves, by glucocorticoids [3]. Mononuclear cells represent one of the best-studied primary target cells of glucocorticoids [3–5]. Mononuclear cells possess high-affinity receptors (type II) for glucocorticoids [3,6]. Many elements of the cellular immune response are altered by glucocorticoids [3,7].

Keywords

Corticosteroid Superoxide Hydrocortisone Interferon Arginine 

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© Springer-Verlag London Limited 1997

Authors and Affiliations

  • David H. Brown
  • Bruce S. Zwilling

There are no affiliations available

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