INTRAVENOUS-INFUSION OF TRIDIHOMO-GAMMA-LINOLENOYL-GLYCEROL REDUCES LEUKOTRIENE-B4 PRODUCTION IN THE RAT AND RABBIT

1. We have formulated an infusible emulsion of 10% tridihomo-gamma-lin olenoyl-glycerol (94% pure) and investigated the effects of its infusi on on leukotriene B4 production. 2. We infused the emulsion into the e ar veins of two rabbits in a dose of 0.8 g of tridihomo-gamma-linoleno yl-glycerol/kg. Polymorphonuclear leucocytes were obtained from rabbit s before the infusion, and 6, 24, 72 and 168 h after. The ionophore-st imulated leukotriene B4 production by polymorphonuclear leucocytes was reduced to about 50% of baseline as early as 6 h after the infusion a nd remained reduced until 24 h after the infusion. 3. To closely inves tigate the changes in leukotriene B4 production at 6 h after the infus ion, we infused 1.0 g of tridihomo-gamma-linolenoyl-glycerol/kg into t he tail veins of eight male Wistar rats. Six hours later, peritoneal m acrophages were obtained from four rats for the analysis of ionophore- stimulated leukotriene B4 production. Peritoneal cells and blood sampl es were also obtained from the remaining rats for fatty acid analysis. Another eight rats were used without prior infusion for baseline dete rmination. 4. The production of leukotriene B4 by macrophages was sign ificantly reduced to 42% of baseline, and the plasma free dihomo-gamma -linolenic acid was markedly increased from 0.26 to 4.82 mol%, in 6 h. 5. We conclude that the infusion of a tridihomo-gamma-linolenoyl-glyc erol emulsion is able to decrease leukotriene B4 production and to inc rease the dihomo-gamma-linolenic acid concentrations in the plasma and peritoneal cells of rats in 6 h.