Decreased brain glucose utilization in patients with Cushing's disease.
Glucocorticoid hormones affect glucose use in different tissues, and the results of several experimental studies have suggested that glucocorticoids have a central action on cerebral metabolism. PET, using the radiotracer 18F-fluorodeoxyglucose (FDG), permits the measurement of cerebral glucose metabolism.


METHODS
To investigate whether cerebral glucose metabolism would be altered in patients with increased plasma glucocorticoid levels, we analyzed the FDG PET studies that were done on 13 patients with Cushing's disease and compared the results with those obtained in 13 age-matched normal control subjects. A second FDG PET scan was performed on 4 patients after surgical removal of the pituitary adenoma.


RESULTS
Patients with Cushing's disease had a significant reduction in cerebral glucose metabolism compared with normal controls. In the patients on whom a second PET scan was performed, there was a trend toward increased glucose metabolism on the second scan when comparing pre- and postsurgery values for each patient.


CONCLUSIONS
We suggest that the decreased cerebral glucose metabolism we observed in Cushing's disease is attributable to increased glucocorticoid levels, and we speculate that abnormal cerebral glucose metabolism might contribute to the cognitive and psychiatric abnormalities that are frequently observed in patients with Cushing's disease.
Brunetti
A
A
Neuroimaging Branch, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.
Fulham
M J
MJ
Aloj
L
L
De Souza
B
B
Nieman
L
L
Oldfield
E H
EH
Di Chiro
G
G
D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D016022:Case-Control Studies; D003480:Cushing Syndrome / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000523:psychology; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D005938:Glucocorticoids / Q000097:blood; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D014055:Tomography, Emission-Computed
D005462:Fluorine Radioisotopes; D005938:Glucocorticoids; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose