DECREASED RELEASE OF NITRIC-OXIDE (NO) BY ALVEOLAR MACROPHAGES AFTER IN-VIVO LOADING OF RATS WITH EITHER IRON OR ETHANOL

Alveolar macrophages were isolated by pulmonary lavage from rats which had been either chronically overloaded with iron by intraperitoneal i njections of iron dextran for four weeks, or rendered alcoholic by adm inistration of increasing concentrations of alcohol vapour, also for f our weeks. Although the hepatic iron content increased in both groups of animals, only the macrophages isolated from the iron-loaded animals showed a significant increase in iron content (P = < 0.05). Furthermo re, in these macrophages there was a significant increase in oxidative tone as demonstrated by a six fold increase in superoxide dismutase a ctivity. In both the iron-loaded and chronically alcoholised macrophag es, there was a significant diminution in nitric oxide release after s timulation with lipopolysaccharide and/or interferon-gamma, which impa ired the ability of both of these groups of macrophages to inhibit the germination of spores from the fungus Rhizopus, a nitric oxide-depend ent process. Such an alteration in nitric oxide release reduces the ma crophage's microbicidal activity. (C) 1998 Elsevier Science Inc.