Regional cerebral glucose utilization in the immature rat: effect of hypoxia-ischemia

The 2-deoxy-[14C]-glucose (2-DG) method of Sokoloff was used to assess regional cerebral glucose utilization (CGU) in the immature rat. The 7-d postnatal rats received 2.5 muCi 2-DG subcutaneously, after which blood was collected for measurement of plasma glucose and 2-DG activity at intervals up to 90 min. The brains of the 90-min rat pups either were frozen for analysis of glucose concentration and chromatographic separation of 2-DG and 2-DG-6-phosphate or for [14C]-autoradiography. A lumped constant of 0.55 was calculated from plasma and brain glucose levels of 6.4 and 1.62 mmol/L.kg, respectively. Of the [14C] activity in brain, 75.6% was in the 2-DG-6-phosphate fraction; this percent was substituted for K1*, K2*, and K3* in the Sokoloff equation. Cerebral hemispheric CGU (n = 6) averaged 11.4 +/- 1.5 mumol/100 g/min, 1/10 the value of adult rat brain. Rates in 16 brain structures (n = 10) ranged from 7.8 (frontal white matter) to 16.9 (cerebellum) mumol/100 g/min. During hypoxia-ischemia (unilateral common carotid artery ligation combined with exposure to 8% oxygen), the lumped constant increased to 1.04, and 99% of 2-DG was converted to 2-DG-6-phosphate. Increases in CGU occurred in all eight structures of the cerebral hemisphere ipsilateral to the carotid artery occlusion (n = 9), ranging from 287% (frontal white matter) to 445% (striatum) of control values (p less than 0.05). Relatively comparable elevations in CGU (234-435% of control) occurred in the contralateral cerebral hemisphere, which were not significantly different from those of the ipsilateral hemisphere.(ABSTRACT TRUNCATED AT 250 WORDS)