BRAIN GLUCOSE-METABOLISM IN HYPOBARIC HYPOXIA

Hypobaric hypoxia at one-half atmospheric pressure for 3 wk was report ed to increase the brain capillary density and glucose transport at th e blood-brain barrier in the adult rat. We examined the metabolic conc omitants of these alterations in rats subjected to the same hypoxic in sult. Hypoxic rats increased brain glucose and lactate concentrations and decreased brain glycogen. However, hypoxia had no significant effe cts on regional brain levels of ATP and phosphocreatine or on intracel lular pH, indicating successful adaptation to the hypoxic insult. 2-De oxyglucose studies showed that hypoxia increased the regional metaboli c rate for glucose by 10-40%. These results indicate increased glycoly sis in the hypoxic rat brain, which probably underlies the increased d ensity of glucose transporters in brain microvessels and the increased blood-to-brain glucose influx in hypoxia.