Elevation by Oxidative Stress and Aging of Hypothalamic-Pituitary-Adrenal Activity in Rats and Its Prevention by Vitamin E
| Autor: | Tadashi Shinkai, Hirokatsu Takatsu, Kouichi Abe, Takeyuki Takahashi, Naoko Kobayashi, Shiro Urano, Taiji Machida |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2009 |
| Předmět: |
Vitamin
medicine.medical_specialty Thiobarbituric acid medicine.medical_treatment Clinical Biochemistry Medicine (miscellaneous) vitamin E Biology medicine.disease_cause chemistry.chemical_compound Corticosterone Internal medicine medicine HPA activity Hyperoxia Nutrition and Dietetics Vitamin E aging Endocrinology chemistry Hypothalamus Oxidative stress Original Article medicine.symptom corticosteroid receptor Hormone |
| Zdroj: | Journal of Clinical Biochemistry and Nutrition |
| ISSN: | 1880-5086 0912-0009 |
| Popis: | The present study was conducted in order to determine whether oxidative stress during aging involves dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis in association with the emergence of cognitive deficits. When young rats were subjected to oxidative stress in the form of hyperoxia, thiobarbituric acid reactive substances, conjugated diene and lipid hydroperoxides increased markedly in the HPA axis. Vitamin E inhibited such increases in lipid peroxides in each organ. Levels of corticotrophin-releasing hormone in the hypothalamus and plasma levels of adrenocorticotrophic hormone and corticosterone were markedly elevated in young rats exposed to hyperoxia. However, young rats fed vitamin E-supplemented diets showed no abnormal hormone secretion, even after being subjected to hyperoxia. Furthermore, glucocorticosteroid receptors (GR) in pyramidal cells in the Cornus ammonis 1 region of the hippocampus in young rats were markedly decreased by oxidative stress. Similar phenomena were also observed in normal aged rats and young rats fed vitamin E-deficient diet kept in a normal atmosphere. Vitamin E supplementation prevented the decrease in GR in the hippocampus and the increase in corticosterone secretion caused by hyperoxia. These results suggest that oxidative stress induces oxidative damage in the hippocampus and the HPA axis during aging, resulting in a cognitive deficit in rats, and that negative-feedback inhibition on HPA activity was markedly dampened due to an increase in corticosterone levels caused by loss of GR. |
| Databáze: | OpenAIRE |
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