Changes in Energetic Metabolism of Rat Myocardium during Acclimation to High Altitude

Abstract

The results reported in this paper refer to the modifications of energetic equilibrium in the myocardium tissue, involved by altitude chronic hypoxia. Experiments have been done on adult rats (males and females) placed in the Jungfraujoch station, in the Alps, at 3,500 m. The obtained data were compared to control animals, bred in Geneva. On the first days of stay at high altitude, a significant fall of tissue energy charge, due to the non-modified enzyme levels in comparison with the controls, was observed. After several weeks of stay in chronic hypoxia, the metabolic modifications leading to the improvement of energy production and to the achievement of a new equilibrium state, take place. In acclimatized animals some good correlation, between the energy charge and the activity of glycolytic enzymes (PGK and PK) ensuring the ATP regeneration, is established.

Expression of lactate dehydrogenase A and B genes in different tissues of rats adapted to chronic hypobaric hypoxia

“…If LDH B gene is generally considered not to respond to low oxygen supply [Ebert et al, 1996], some studies have demonstrated that its transcription can be down‐regulated by hypoxia in retina [Buono and Lang, 1999]. On the opposite, earlier physiological studies using rats as a model have shown that LDH B activity in skeletal muscle and heart [Barrie and Harris, 1976; Vergnes and Moret, 1976] could be up‐regulated during chronic hypoxia. Rat LDH B gene promoter structure is poorly documented but in fish, it exhibits a putative hypoxia response element [Rees et al, 2001].…”