EVALUATION OF PURINE NUCLEOTIDE LOSS, LIPID-PEROXIDATION AND ULTRASTRUCTURAL ALTERATIONS IN POSTHYPOXIC HEPATOCYTES

1. Hypoxic alterations in isolated rat hepatocytes were demonstrated b y a 90% ATP loss during 60 min of ischaemia and temporary increases of nucleotide degradation products. 2. The oxidative stress during reoxy genation was demonstrated in these cells by a decrease in reduced glut athione (GSH) concentration (30%) and a threefold increase in lipid pe roxidation products such as 4-hydroxynonenal and thiobarbituric acid-r eactive substances (TBA-RSs). The tremendous GSH loss could not be bal anced by the slight oxidized glutathione (GSSG) increase during reoxyg enation. 3. For the first time the involvement of free radicals was di rectly demonstrated using electron spin resonance (ESR) spectroscopy i n reoxygenated liver cells. Using the spin trap 5,5-dimethylpyrroline- 1-oxide (DMPO), a carbon-centred radical and the adduct of the hydroxy l radical could be detected during early reoxygenation. 4. Morphologic al alteration of cells was observed, beginning during hypoxia and incr easing during post-hypoxic reoxygenation. Electron microscopic finding s of hypoxic and posthypoxic cell damage included pyknosis of nuclei, spherical transformation of mitochondria and increased number of vesic les.