Elevation by oxidative stress and aging of hypothalamic-pituitary-adrenal activity in rats and its prevention by vitamin E

Naoko Kobayashi, Taiji Machida, Takeyuki Takahashi, Hirokatsu Takatsu, Tadashi Shinkai, Kouichi Abe, Shiro Urano

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)207-213
Number of pages7
JournalJournal of Clinical Biochemistry and Nutrition
Volume45
Issue number2
DOIs
Publication statusPublished - 2009 Sep
Externally publishedYes

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Keywords

  • Aging
  • Corticosteroid receptor
  • HPA activity
  • Oxidative stress
  • Vitamin E

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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