INFLUENCE OF DIETARY-FAT ON THE EFFECT OF ENDOTOXIN ON MURINE HEPATICPEROXISOMES

This study investigates the effects of either a high-fat diet or endot oxin on peroxisome metabolism as assessed by measuring catalase activi ty, catalase mass, and peroxisomal beta-oxidation. Three mouse strains C3H/HeJ, BALB/c, and C57BL/6J were fed either a low-fat or a high-fat diet and injected intraperitoneally with 1 mu g Escherichia coli lipo polysaccharide, These parameters were not different in C3H/HeJ mice fe d a high-fat diet compared with controls fed a low-fat diet, Total liv er catalase activity and peroxisomal beta-oxidation were higher in BAL B/c mice fed high fat diet compared with low-fat controls, Total liver catalase activity, catalase mass and peroxisomal beta-oxidation incre ased to the greatest extent in C57BL/6J mice fed a high-fat diet, Endo toxin treatment did not alter any of the parameters in mice fed a low- fat diet, Among mice fed a high-fat diet, endotoxin did not affect hep atic catalase or peroxisomal beta-oxidation in the C3H/HeJ mice, decre ased catalase activity in BALB/c mice (28%), and greatly decreased bot h catalase (66%) and peroxisomal beta-oxidation (69%) in C57BL/6J mice , The decrease in catalase activity in C57BL/6J mice was apparently be cause of an inactivation of the enzyme as determined by the activity/m ass ratio, Thus, endotoxin is showed to inhibit both catalase and pero xisomal beta-oxidation in mice and the sensitivity to endotoxin is gre atest in C57BL/6J mice fed a high-fat diet.