Uptake of dihomo-gamma-linolenic acid by murine macrophages increases series-1 prostaglandin release following lipopolysaccharide treatment

Administration of dihomo-gamma-linolenic acid is useful for atopic dermatitis and atherosclerosis in mice; however, the metabolites of dihomo-gamma-linolenic acid have been little studied. We employed a method which enabled simultaneous analysis of nine prostaglandins using liquid chromatography-tandem mass spectrometry, and determined the concentrations of prostaglandins in the supernatants of cultures of mouse peritoneal macrophages stimulated with lipopolysaccharide after pre-incubation with dihomo-gamma-linolenic acid, arachidonic acid, or eicosapentaenoic acid. Accumulated prostaglandin concentrations from mouse macrophages with dihomo-gamma-linolenic acid uptake increased in a dihomo-gamma-linolenic acid concentration-dependent fashion. These increases were mainly due to prostaglandin D(1) and prostaglandin E(1). The order of accumulated prostaglandin concentrations was dihomo-gamma-linolenic acid>arachidonic acid>eicosapentaenoic acid in supernatants with the same concentration of polyunsaturated fatty acid. Since mouse macrophages can clearly produce series-1 prostaglandins, they must be formed in vivo. These findings suggest that the effects of dihomo-gamma-linolenic acid on diseases may be due to series-1 prostaglandins.