title: Gender-specific alterations of cerebral metabolites with aging and cortisol treatment.
abstract: Excess availability of the adrenocortical glucocorticoid hormone cortisol has been correlated with structural brain changes and a decline of cognitive functions during aging. Pertinent studies need to consider gender as a potential confound because of sexual dimorphism in the regulation of hypothalamus-pituitary-adrenal axis activity. In vivo localized proton magnetic resonance spectroscopy of male and female tree shrews revealed similar concentrations of cerebral metabolites in young adult animals but gender-specific alterations with aging as well as in response to cortisol treatment. In comparison with adult tree shrews, aged males had reduced concentrations of N-acetylaspartate (-33%; P<0.01) and total creatine (-34%; P< 0.01). These findings are in line with the occurrence of neuronal loss. In contrast, aged females exhibited increased concentrations of choline-containing compounds (+27%; P<0.05) which--together with a tendency for increased creatine (+24%) and myo-inositol (+14%)--is indicative of glial proliferation. After chronic administration of cortisol (4 mg/day for 28 days), male but not female tree shrews showed a specific reduction of the choline-containing compounds (-29%; P< 0.05). The observed sex differences with age are likely to result from differences in the regulation of stress-related hormones which is further supported by the gender-specific responses to cortisol.
authors.affiliation: Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, 37070 Göttingen, Germany. tmichae@gwdg.de
authors.forename: T
authors.initials: T
authors.lastname: Michaelis
authors.forename: G
authors.initials: G
authors.lastname: de Biurrun
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
authors.forename: J
authors.initials: J
authors.lastname: Frahm
authors.forename: F
authors.initials: F
authors.lastname: Ohl
authors.forename: E
authors.initials: E
authors.lastname: Fuchs
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D001931:Brain Mapping; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006854:Hydrocortisone / Q000502:physiology*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D012737:Sex Factors; D014418:Tupaiidae
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline; D006854:Hydrocortisone