Dehydrogenase activity in the blood and brain after adaptation to intermittent hypoxia

Activities of LDH (lactate dehydrogenase) and alpha-HBDH (alpha-hydroxybutyric dehydrogenase) were measured in rats after intermittent exposure to the aerogenic hypoxia at a simulated altitude of 7000 m during the postnatal period (since birth to the 18th day) or in adulthood (older than the 90th day), except days 6, 7, 13, and 14 of the experiment. Enzymatic activity was measured using standard test kit (Biochemical Test Combination, Boehringer). Twenty hours after the last exposure to hypoxia, the activity of both enzymes was elevated in the serum and in the brain of the young rats. In contrast, in adult rats, the exposure to hypoxia did not result in changes of the enzyme activity in the serum or in the brain. Our results indicate that, whereas in adults the biochemical adaptation to repeated aerogenic hypoxia has no effects on the enzymatic activities of dehydrogenases, the same stimulus during the early postnatal period brings about rising of the aerobic glycolysis contribution to the total energy balance. Such increase is enabled by the increase of LDH and alpha-HBDH activities.