Lipid peroxidation in isolated rat hepatocytes measured by ethane and n-pentane formation

Abstract

Abstract. Isolated rat hepatocytes (1 x 107 cells/ml) were aerobically incubated in Eagle's Minimum Essential Medium which contained 2.0% albumin. As potential parameters of lipid peroxidation ethane and n-pentane formed were measured in samples obtained from the gas phase above the incubation mixture. 15-30 nmol ethane or n-pentane were produced by 107 hepatocytes within 90 min. Carbon tetrachloride (CC14) or ADP-complexed ferrous ions stimulated ethane and n-pentane formation considerably, depending on the concentrations of the compounds. With CC14 107 cells formed max 180 nmol ethane and 140 nmol n-pentane within 90 min incubation, whereas with Fe(II) max 130 nmol ethane and 220 nmol n-pentane could be detected.When n-pentane was added to the gas phase above the incubation mixture containing either medium or medium plus hepatocytes its amount decreased by 30% within the first 5 min of incubation. However, afterwards only minor amounts of n-pentane disappeared, even in the presence of hepatocytes. This indicates that n-pentane equilibrates with the cell suspension under the conditions used.Cell viability, as determined by the release of lactate dehydrogenase into the medium and by the uptake of trypan blue by the cells, and the recovery of the cells decreased only in presence of relatively high concentrations of CC14, or Fe(II) respectively. However, a maximal effect on ethane and n-pentane formation was reached already with lower concentration.

Biological Activities of Polyphenols from Grapes

“…Being most the notable bioactivity of phenolic compounds from grapes, the antioxidative characteristics have been widely studied, including scavenging of free radicals, inhibition of lipid oxidation, reduction of hydroperoxide formation, and so on [18,19]. Several methods were employed to evaluate the antioxidant capacities of phenolic compounds extracted from various grapes or different parts of grapes, such as the 1,1-diphenyl-2-picryhidrazyl (DPPH) method [55], oxygen radical absorbance capacity (ORAC) assay [56], crocin bleaching assay (CBA) [57], 2,2'-azino-bis-(3ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay [58], the thiobarbituric acid reactant substances (TBARS) [59], Trolox equivalent antioxidant capacity (TEAC) assay [60], and the ferric reducing antioxidant power (FRAP) assay [61]. Using these methods above, notable antioxidant activities were found for grape wine and juice and the extracts from different parts of grapes.…”

Biological Activities of Polyphenols from Grapes

“…Several methods were employed to evaluate the antioxidant capacities of phenolic compounds extracted from various grapes or different parts of grapes, such as the 1,1-diphenyl-2-picryhidrazyl (DPPH) method [55], oxygen radical absorbance capacity (ORAC) assay [56], crocin bleaching assay (CBA) [57], 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay [58], the thiobarbituric acid reactant substances (TBARS) [59], Trolox equivalent antioxidant capacity (TEAC) assay [60], and the ferric reducing antioxidant power (FRAP) assay [61]. …”

Iron loading of cultured hepatocytes. Effect of iron on 5-aminolaevulinate synthase is independent of lipid peroxidation

“…Although lipid peroxidation has been detected in iron-loaded rats by measuring expired ethane (Dillard & Tappel, 1979;Dougherty et al, 1981), it is not certain that the source of ethane was hepatic. Other workers using isolated rat hepatocytes exposed to various forms of iron have also detected lipid peroxidation by various means (Hogberg et al, 1975;Stacey & Priestley, 1978;Dianzani et al, 1981;de Ruiter et al, 1982;Stacey & Kappus, 1982), but these cells may have lacked normal protection against lipid peroxidation due to limited viability (Tanaka et al, 1978) or selenium deficiency (Newman & Guzelian, 1982).…”