Effect of temperature on metabolic rates of liver and brown fat homogenates.
Temperature effects in vitro on oxygen metabolic rates of brown fat and liver homogenates from control and cold-acclimated rats
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Temperature effects in vitro on oxygen metabolic rates of brown fat and liver homogenates from control and cold-acclimated rats
Liver xanthine dehydrogenase change relation to uric acid excretion during adaptation period in chicks fed 25-75 percent isolated soybean protein
Repeated acceleration effects on histological structure of dog liver
Optimal tolerable stress-time effects of acceleration on histology of monkey liver
Hypothermia induced alterations in biochemical processes studied with isolated rat liver perfused at low temperature
Long microextensions on cultivated human liver cells, using scanning electron microscope
Hyperoxia and hypoxia effects on mitotic activity in regenerating and normal rat liver exposed to environmental conditions
Purification and properties of diphosphopyridine nucleotide-linked glycerol 3-phosphate dehydrogenases from chicken breast muscle and liver
Enzyme beta-hydroxybutyrate dehydrogenase concentration in mitochondria from bovine and sheep liver
Chloride and sulfhydryl activators in glucagol degradation and secretion by purified rat liver dipeptidyl aminopeptidase I /Cathepsin C/
Amino acid metabolism time dependent variations, studying tyrosine transaminase rhythm in rat liver
Prolonged hyperoxia effects on lipid synthesis in rat liver and adipose tissue slices
Mitotic response to various diets in normal and regenerating rat liver
Stimulatory effects of hypobaric hyperoxia on lipid synthesis in rat liver and adipose tissues under free feeding
Liver tissue obtained from adult rats exposed to 3800 m altitude for intervals ranging from 1.5 hr to 63 days was examined by enzymatic analysis. During the first 3 hr of exposure, an immediate decrease in rephosphorylation of high-energy phosphates led to reduced glycogenesis and eventual pileup of AMP, pyruvate, fructose 1,6-diphosphate, glucose 6-phosphate, and glucose. This was accompanied by a reduction of pentose phosphate pathway activity. After 3 to 6 hr, a secondary adjustment of substrate concentrations occurred along with the apparent facilitation of phosphofructokinase. This secondary adjustment appears to increase anaerobic production of ATP and represents a significant intracellular contribution to the acclimatization process at high altitude.
Longitudinally and transversely applied g-forces as intolerable levels cause damage to the interlobular veins of the liver, with maximum damage caused by dorso-ventral g-force application. The portal vein system is more resilient with respect to g-forces at the limit of tolerance.
Experiments on albino rats showed that 30 day hypokinesia changes the reaction of the liver to cholagogues. The choleretic action of oxaphenamide as well as its inhibitory effect on synthesis of bile acids diminishes, while the influence of bilirubin secretion increases.
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.