Horm Metab Res 2004; 36(6): 370-375
DOI: 10.1055/s-2004-814569
Review
© Georg Thieme Verlag Stuttgart · New York

Orexins (Hypocretins) and Adrenal Function

O.  Jöhren1 , N.  Brüggemann1 , P.  Dominiak1
  • 1Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Germany
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Publication History

Received 20 November 2003

Accepted without Revision 2 Februar 2004

Publication Date:
07 July 2004 (online)

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Abstract

The recently discovered neuropeptides orexin A and B regulate feeding behavior, neuroendocrine and autonomic functions, and sleep-wakefulness by central mechanisms. The expression of orexins and orexin receptors in various peripheral organs and the presence of orexin A in blood indicate the existence of a peripheral orexin system. In rat and human adrenal glands, both OX1 and OX2 receptor subtypes have been described with a predominant expression of OX2 receptors in the adrenal cortex. In male rats, adrenocortical OX2 receptors are much higher expressed than in female rats. Various experimental data demonstrate a stimulatory effect of orexins on the secretion of adrenocortical steroids, mainly on glucocorticoids. Some results also suggest the regulation of catecholamine synthesis and release by orexins. Whether the gender-dependent expression of adrenocortical OX2 receptors has functional correlates awaits future clarification. As plasma orexin appears to rise during hunger and hypoglycemia, orexins may link adrenal functions with energy homeostasis.

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Dr. O. Jöhren

Institute of Experimental and Clinical Pharmacology and Toxicology · University of Lübeck

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