title: Energy status and oxidation-reduction status in rat liver at high altitude (3.8 km).
abstract: Adult male rats were exposed to 3.8-km altitude for intervals ranging from 1 h-60 d. Liver samples were taken under light ether anesthesia and were examined by enzymatic analyses. Within 1-6 h of hypoxic exposure, ATP levels decreased while ADP and AMP levels increased, producing a fall in calculated ATP/ADP and adenylate charge ratios. Concurrently, lactate/pyruvate and alpha-glycerophosphate/dihydroxyacetone phosphate ratios increased markedly. Direct measurements of cellular pyridine nucleotides indicated increased NADH/NAD and NADPH/NADP ratios. Levels of total adenosine phosphates and pyridine nucleotides decreased in a significant accompanying response. Many metabolite levels and calculated ratios returned to near-normal values within 1 week of exposure, indicating secondary intracellular adjustments to hypoxic stress; however, persistence of that stress is reflected in lactate concentrations and both substrate redox ratios. Results support and explore concepts that increased oxidation-reduction status and decreased energy status are primary events during hypoxia.
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000531:Altitude; D000818:Animals; D004099:Dihydroxyacetone Phosphate / Q000378:metabolism; D004734:Energy Metabolism; D005994:Glycerophosphates / Q000378:metabolism; D007773:Lactates / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D011773:Pyruvates / Q000378:metabolism; D051381:Rats; D013997:Time Factors
chemical_list: D005994:Glycerophosphates; D007773:Lactates; D011773:Pyruvates; D009243:NAD; D000249:Adenosine Monophosphate; D009249:NADP; D004099:Dihydroxyacetone Phosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate