Cortisol levels are positively correlated with hippocampal N-acetylaspartate.
BACKGROUND
This study examined the relationship of hypothalamic-pituitary-adrenal measures and hippocampal N-acetylaspartate (NAA) in posttraumatic stress disorder (PTSD) patients and control subjects.


METHODS
Eleven patients with combat-related PTSD and 11 control subjects were evaluated with magnetic resonance spectroscopy as well as by morning salivary cortisol samples before and after administration of low-dose dexamethasone (.5 mg).


RESULTS
Left hippocampal NAA was strongly associated with both pre-dexamethasone cortisol levels (n = 22, r =.53, p =.013) and post-dexamethasone cortisol levels (n = 22, r =.63, p =.002). After accounting for clinical symptom severity and hippocampal volume, cortisol levels accounted for 21.9% of the variance (F = 5.6, p =.004) in left hippocampal NAA and 12.6% of the variance (F = 3.2, p =.035) in right hippocampal NAA.


CONCLUSIONS
This study shows a positive relationship between cortisol levels and hippocampal NAA in subjects without hypercortisolemia. Within the range of values seen in our subjects, cortisol may have a trophic effect on the hippocampus.
Neylan
Thomas C
TC
Mental Health Service, San Francisco Department of Veterans Affairs Medical Center, San Francisco, California 94121, USA.
Schuff
Norbert
N
Lenoci
Maryanne
M
Yehuda
Rachel
R
Weiner
Michael W
MW
Marmar
Charles R
CR
D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism*; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D003907:Dexamethasone / Q000008:administration & dosage; D005938:Glucocorticoids / Q000008:administration & dosage; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay / Q000379:methods; D012044:Regression Analysis; D012463:Saliva / Q000378:metabolism; D013223:Statistics as Topic; D013313:Stress Disorders, Post-Traumatic / Q000378:metabolism*; D014728:Veterans
D005938:Glucocorticoids; D001224:Aspartic Acid; D003907:Dexamethasone; C000179:N-acetylaspartate; D006854:Hydrocortisone