Brain Carbohydrate Metabolism in Developing Rats During Hypercapnia
Brain Carbohydrate Metabolism in Developing Rats During Hypercapnia
复制标题
高碳酸血症期间发育中大鼠的脑碳水化合物代谢
作者：
A. Miller;D. Corddry
翻译后摘要：大脑葡萄糖代谢进行了研究，在发育中的大鼠在出生后10和20天的正常和高碳酸血症的条件下。取出脑并用冷冻吹制装置在1秒内冷冻。用[2 - 14 C]葡萄糖和[3 H]脱氧葡萄糖作为示踪剂测量葡萄糖利用率。通过标准酶促技术测定代谢产物。从[3 H]脱氧葡萄糖磷酸化的数据表明，正常的大脑葡萄糖利用率增加了近三倍之间的第10和第20天出生后。从20日龄对照组中两种同位素的相对利用率来看，似乎约25%源自[2 - 14 C]葡萄糖代谢的14 C标记物从大脑中丢失（可能作为乳酸盐），而不是进入克雷布斯循环。在高碳酸血症条件下（20% CO2 - 21% O2 - 59% N2），两个年龄组的大脑葡萄糖利用率均降低一半，许多中间代谢物的浓度也逐渐降低。得出结论，这些代谢产物被用来补充葡萄糖作为呼吸的燃料，而不是被泄漏到血液中丢失的基础进行了讨论。尽管10日龄和20日龄大鼠的脑葡萄糖代谢存在差异，但它们对高碳酸血症的反应非常相似：葡萄糖利用率被20%的CO2降低到与原始速率大致相同的比例，内源性代谢物（特别是谷氨酸盐和乳酸盐）似乎被氧化为替代燃料。
Abstract: Brain glucose metabolism was studied in developing rats at ages 10 and 20 days postnatal under normal and hypercapnic conditions. Brains were removed and frozen within 1 s with a freeze‐blowing apparatus. Glucose utilization was measured with [2‐14C]glucose and [3H]deoxyglucose as tracers. Metabolites were determined by standard enzymatic techniques. Data from [3H]deoxyglucose phosphorylation indicated that normal brain glucose utilization increased almost threefold between the 10th and 20th postnatal days. From the relative rates of utilization of the two isotopes in the 20‐day‐old control group, it appeared that about 25% of 14C label derived from metabolism of [2‐14C]glucose was lost from brain (probably as lactate) rather than entering the Krebs cycle. Under hypercapnic conditions (20% CO2‐21% O2‐59% N2), rates of glucose utilization by brain were decreased by one‐half at both ages and there were progressive decreases in the concentrations of many intermediary metabolites. The bases for concluding that these metabolites were used to supplement glucose as a fuel for respiration, rather than being lost by leakage into blood, are discussed. Despite the differences in brain glucose metabolism between 10‐day‐old and 20‐day‐old rats, their responses to hypercapnia are remarkably similar: Rates of glucose utilization are reduced to approximately the same proportion of the original rate by 20% CO2, and endogenous metabolites (particularly glutamate and lactate) appear to be oxidized as replacement fuels.