Metabolite Assay in Frozen Samples of Liver Tissue

Bücher, Th.; Krejci, Kaj; Rüßmann, W.; Schnitger, H.; Wesemann, W.

doi:10.1016/b978-1-4832-3260-7.50035-4

Cited by 17 publications

(1 citation statement)

References 14 publications

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“…Adenyl ate kinase is obviously extremely important in maintaining the adenylate charge, because the observed concentration of the adenine nucleotides changes [32][33][34] in such a way as to implicate the equilibrium constant of the adenylate kinase reaction [35]. The high cyto plasmic adenylate kinase levels and their constancy ( fig.…”

Section: Enzymes O F Adenine Nucleotide Metabolismmentioning

confidence: 99%

Development of Enzymes of Energy Metabolism in Rat Heart

Andrés¹,

Satrústegui²,

Machado³

1984

Neonatology

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The behavior of several enzymes was studied during rat heart development (4 days before birth to adult stage). Hexokinase has its highest activity during the fetal period; it decreases at birth and remains with low activity in the adult. The α-glycerophosphate dehydrogenase and α-glycerophosphate oxidase profiles are similar up to the 15th day of development. From there onwards, both profiles diverge, the cytoplasmic activity increasing 3-fold, while the mitochondrial activity remains unchanged. The developmental profiles of the malate dehydrogenases are almost parallel. The development of citrate synthase and succinate dehydrogenase results in a 2- to 4-fold increase in their activities. However, ATPase increases dramatically (20-fold) over the same period. With respect to the enzymes of the adenine nucleotide metabolism, adenylate kinase is fully expressed throughout all ages examined, showing no variation during development. AMP deaminase and creatine kinase increase during development, the cytoplasmic creatine kinase reaching a high level at birth whereas the increases of the mitochondrial enzymes take place gradually during development.

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Section: Enzymes O F Adenine Nucleotide Metabolismmentioning

confidence: 99%

Development of Enzymes of Energy Metabolism in Rat Heart

Andrés¹,

Satrústegui²,

Machado³

1984

Neonatology

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Differential Effects of Hypoxia on the Disposition of Propranolol and Sodium Taurocholate by the Isolated Perfused Rat Liver

et al. 1984

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Although the adverse effect of hypoxia on drug metabolism is well documented in subcellular systems, its effect on drug clearance by the intact liver has not been defined. This study was undertaken in the isolated perfused rat liver to examine the effects of acute hypoxia on the hepatic elimination of two highly cleared substances--propranolol and sodium taurocholate. Hypoxia was established by equilibrating the perfusate with 100% nitrogen rather than 100% oxygen. This led to a fall in portal vein pO2 from 300 to 30 mm Hg, and a 10-fold rise in hepatic venous lactate:pyruvate ratio, indicating a profound alteration in hepatic cellular redox state. In bolus dose studies, propranolol uptake was unimpaired by hypoxia, with a monoexponential decline in perfusate concentrations from 2,000 to 30 ng per ml, (t1/2 uptake = 2.5 min). After 20 min of hypoxia, perfusate propranolol concentrations rose from 30 to 80 ng per ml, indicating release of propranolol from liver back into the perfusate. Reoxygenation of perfusate restored hepatic extraction of propranolol to normal (t1/2 uptake = 2.37 +/- 0.19 min vs. 2.55 +/- 0.60 min p greater than 0.1) such that perfusate concentrations were undetectable by 30 min. In steady-state studies, perfusate propranolol concentrations rose from 1.55 +/- 0.50 to 4.08 +/- 1.47 micrograms per ml (p less than 0.005), after 1 hr of hypoxia indicating a change in propranolol clearance from 15 ml per min to less than 6 ml per min. Reoxygenation resulted in a fall in perfusate propranolol concentrations towards control values (2.78 +/- 1.13 vs. 1.80 +/- 0.41 micrograms per ml, p greater than 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

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