Contribution of central SGK-1 to the acute phase responses of mice to social isolation

Takao Kaji, Katsunori Nonogaki

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

Ghrelin is a hormone produced mainly by P/D1 cells which line the fundus of the stomach and epsilon cells of the pancreas that stimulate hunger. Ghrelin exists in an endocrinologicaly inactive (des-acyl ghrelin) and active (noctanoyl-modified ghrelin) forms. The serum- and glucocorticoid-inducible kinase 1 (SGK-1) is a member of the AGC family of serine/threonine protein kinase. In this study, mice were isolated individually or in groups, and deprived from food supply for a period of 24-h. Despite decreases in plasma corticosterone levels and no changes in plasma des-acyl ghrelin, and the expression of hypothalamic neuropeptide Y and proopiomelanocortin, plasma active ghrelin levels and the expression of hypothalamic SGK-1 increased in the acute-isolated mice. Injection of SGK-1 small interfering RNA (siRNA) oligonucleotide into the third cerebral ventricle suppressed the acute social isolation-induced decreases in body weight and increases in plasma active ghrelin levels. Pretreatment with phentolamine (alpha-adrenergic receptor antagonist) but not alprenolol (beta-adrenergic receptor antagonist), partially but significantly suppressed the decreases in body weight induced by acute isolation stress. These finding suggest that isolation stress is a novel inducer of hypothalamic SGK-1 expression. SGK-1 might contribute to the isolation stress-induced body weight reductions and increases in plasma active ghrelin levels via, at least partly, altered central autonomic outflow in mice.

Original languageEnglish
Pages (from-to)1355-1361
Number of pages7
JournalFrontiers in Bioscience - Elite
Volume2 E
Issue number4
Publication statusPublished - 2010 Jan 6

Keywords

  • Active Ghrelin
  • Body weight
  • Fasting
  • Hypothalamus
  • SGK-1
  • Social isolation
  • Sympathetic nervous system

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

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