[Local cerebral glucose utilization in the ethylnitrosourea-induced rat glioma]

Local cerebral glucose utilization (LCGU) of anesthetized rats bearing ethylnitrosourea (ENU)-induced gliomas was studied with 14C-deoxyglucose autoradiography. Single subcutaneous injection of ethylnitrosourea (50 mg/kg) was made to the newborn rats, and animals were used for experiment at 150 to 300 days after birth. Under ketamine anesthesia, 14C-deoxyglucose was injected through a venous catheter, and timed arterial sampling was made. Brains were removed at 45 min after injection, and prepared for macro-autoradiography. LCGU values were measured by the equation developed by Sokoloff et al. In the microtumors (less than 2 mm in diameter), mean LCGU value was 30 mumol/100 g/min, which was significantly (p less than 0.01) lower than mean value of normal cortex (63 mumol/100 g/min). In the macrotumors (greater than 2 mm in diameter). LCGU values in the tumor were separated to high part (mean; 49 mumol/100 g/min) and low part (mean; 38 mumol/100 g/min), which were still lower than mean cortical value and higher than mean white matter value (corpus callosum; 26 mumol/100 g/min). No LCGU changes were noted in the brain tissue adjacent to the microtumors. Whereas, macrotumor significantly reduced LCGU in the adjacent cortex. The present data may indicate that glucose metabolism of the ENU induced glioma and edematous peritumoral brain tissue is lower than that of normal cortex.