The investigation of levels of the peptide adrenomedullin (ADM) and the enzyme tyrosine hydroxylase (TH) in rat tissue after exposure to physiological stress

Abstract

An organism's ability to respond to the external and internal environments is explained in terms of the concept of biological stress. The causes of these responses are called stressors. They may be physical, chemical, emotional, or traumatic. With continued exposure to the stressor the organism enters the stage of resistance and defense. After prolonged exposure to the same stressor the organism may enter the stage of exhaustion. Catecholamines have an important role in maintaining biological homeostasis to stress. Catecholamine biosynthesis starts from tyrosine and in the first step DOPA is synthesized from tyrosine and catalyzed by the enzyme tyrosine hydroxylase (TH). In rats this enzyme activity varies depending on cold stress, exercise and age. The production of adrenomedullin in adrenal medulla, heart and brain also suggest a role for this peptide in the physiological control of homeostasis. In this study TH enzyme activity and adrenomedullin levels were investigated in rat tissues that were excised from animals exposed to 8°C cold for 3 weeks. After cold exposure TH enzyme activities and adrenomedullin levels were changed but also age was found to be a factor. Copyright © 2006 John Wiley & Sons, Ltd.

Adrenomedullin reduces antioxidant defense system and enhances kidney tissue damage in cadmium and lead exposed rats

“…AdM has also been found to possess angiogenic, antiapoptotic, and antimicrobial properties. AdM has been examined in a variety of disease states and studies have shown the pathophysiological effects of AdM under a stress response (Yuksel and Yurekli, 2003;Yurekli and Yarpuzlu, 2006), an inflammatory reaction caused by Henoch-Schonlein purpura (HSP) (Islek et al, 2003), and an anti-inflam-matory in VEGF-induced adhesion molecules (Kim et al, 2003). AdM has also been observed in respiratory vessel endothelium dysfunction in Behcet disease (Evereklioglu et al, 2000), bipolar affective disorder (Savas et al, 2002), Bartter syndrome (Balat et al, 2002), preeclampsia (Celik et al, 2003;Hascalik et al, 2005), and varicocele and impotence .…”