Frerichs K U, Dienel G A, Cruz N F, Sokoloff L, Hallenbeck J M
Stroke Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892.
Am J Physiol. 1995 Feb;268(2 Pt 2):R445-53. doi: 10.1152/ajpregu.1995.268.2.R445.
Rates of glucose utilization (CMRGlc) were determined in some cerebral structures of active warm- and cold-adapted ground squirrels and hibernating ground squirrels with [14C]deoxyglucose (DG) by direct chemical measurement of precursor and products in samples dissected from funnel-frozen brain. The rate of supply relative to demand of glucose and [14C]DG in brain of hibernating animals was similar to or greater than that of controls. [14C]DG cleared from the plasma in hibernators much more slowly than in active animals, and the level of unmetabolized [14C]DG in brain and the integrated specific activity of the precursor pool in plasma exceeded those of the active animals by 4- to 10-fold. At 45 min after an intravenous pulse of [14C]DG, the unmetabolized [14C]DG remaining in the brains of the hibernators accounted for approximately 96% of the total 14C compared with approximately 10-15% in the active animals. The value of lambda, a factor contained in the lumped constant of the operational equation of the [14C]DG method, was estimated for each animal and found to be relatively constant over the sixfold range of glucose levels in the brains of all animals. Calculated CMRGlc in squirrels in deep hibernation was only 1-2% of the values in active animals.
通过对漏斗冷冻大脑中所取样本的前体和产物进行直接化学测量，用[14C]脱氧葡萄糖（DG）测定了活跃的暖适应和冷适应地松鼠以及冬眠地松鼠某些脑结构中的葡萄糖利用率（CMRGlc）。冬眠动物大脑中葡萄糖和[14C]DG的供应与需求速率与对照动物相似或更高。冬眠动物血浆中[14C]DG的清除速度比活跃动物慢得多，大脑中未代谢的[14C]DG水平以及血浆中前体池的综合比活性比活跃动物高出4至10倍。静脉注射[14C]DG脉冲45分钟后，冬眠动物大脑中剩余的未代谢[14C]DG约占总14C的96%，而活跃动物中这一比例约为10 - 15%。为每只动物估算了[14C]DG方法运算方程总括常数中包含的一个因子λ的值，发现在所有动物大脑中葡萄糖水平六倍的范围内该值相对恒定。深度冬眠地松鼠的计算CMRGlc仅为活跃动物值的1 - 2%。
