Glutathione-dependent peroxidative metabolism in the alveolar macrophage

Abstract

A B S T R A C T Phagocytosis by rabbit alveolar macrophages (AM) is accompanied by increases in 02 consumption, glucose oxidation, and H202 formation. Two aspects of the interrelations between these metabolic features of phagocytosis have been studied.First, the following evidence indicates that glutathione, glutathione reductase, and peroxidase serve as a cytoplasmic shuttle between H202 and NADPH-dependent glucose oxidation: (a) AM contain 5.9 mi'moles of reduced glutathione per 108 cells and exhibit glutathione peroxidase and NADPH-specific glutathione reductase activity; (b) oxidized glutathione potentiates NADP stimulation of glucose oxidation; (c) an artificial H202-generating system stimulates glucose oxidation; (d) the cell penetrating thiol inhibitor, N-ethylmaleimide diminishes glucose oxidation. This effect largely depends on inhibition of the glutathione system rather than on inhibition of either H202 formation or enzymes directly subserving glucose oxidation.Second, three potential H202-generating oxidases have been sought. No cyanide-insensitive NADH or NADPH oxidase activity could be detected. D-amino acid oxidase activity was 0.48 ±0.07 U/106 cells with D-alanine as substrate.

Assay of Glutathione in Individual Mouse Peritoneal Macrophages by Capillary Zone Electrophoresis with Electrochemical Detection

“…2C are, first, that there is no correlation with respect to the run number, which proves that the influence of the other substances in macrophages on the determination of GSH has been minimized; and second, that the distribution of values does not follow Gaussian statistics. The mean GSH content for 20 cells is 5.8 Ϯ 2.9 fmol (mean Ϯ SD), which is consistent with the literature value (4.8 -6.0 fmol) (26). A histogram of the data (shown in Fig.…”

“…A total of 20 cells were analyzed consecutively. If the content of GSH in each cell is calculated by comparison of peak height against the peak height of GSH standard, the average amount of GSH in single macrophage is (2.8 Ϯ 1.7) fmol (mean Ϯ SD), which is about one-half of the literature value (4.8 -6.0 fmol) (26). This means that the substances in the cells probably interfere with the determination of GSH.…”

Increased Superoxide Anion Production and Glutathione Peroxidase Activity in Peritoneal Macrophages from Autoimmune-Prone MRL/Mp-lpr/lpr Mice

“…Several investigators have studied the role of en dogenous scavengers of oxygen intermediates in mac rophages [30][31][32][33][34], Murray et al [33] demonstrated that in vitro lymphokine-activated peritoneal macro phages from normal mice increased activities of SOD, GSH Px and catalase in association with augmented production of O; and H^CT. In our experiments, in vitro treatment with LPS similarly increased catalase activity in both MRL/1 (by 39%) and MRL/n (by 34%) macrophages, which confirmed an earlier find ing of Murray et al [33].…”

The Role of Free Radical Reactions in Biological Systems

“…^+ PhSBu-/ + /-BuS- (83) fast and hydrogen abstraction often predominates [166,168,169]. Radical attack on the sulfur of the comparable disulfides, a "softer" and more polarizable center, is faster [166,168,169]; for example, see eqs 81-83. Nucleophilic substitution reactions on the Ο-Ο bond of benzoyl peroxide are much faster than on dialkyl peroxides, as expected, since the leaving group is better.…”