Peripheral benzodiazepine receptors and glucose metabolism in human gliomas

Peripheral benzodiazepine receptors (PBR) are increased in gliomas and augmented glucose metabolism is seen in malignant brain tumors. We investigated the relationship between PBR density (Bmax) and glucose utilization rate (GUR) in 17 patients with cerebral gliomas of different grades. PBR Bmax was assessed by [3H]PK-11195 in vitro binding in surgical specimens and GUR was measured by Positron Emission Tomography with [18F]2-Fluorodeoxyglucose before the surgery. In untreated tumors there was a positive correlation between PBR Bmax and GUR (2r = 0.84). This correlation was not observed in patients who had been treated with radiation and/or chemotherapy prior to surgery (r2 = 0.13). In addition, in untreated patients, the increase in PBR density and GUR appeared to be related to the degree of malignancy.