ABSTRACT
We compared the dietary effects of dihomo-gamma-linolenic acid (DGLA) contained in the DGLA oil produced by a fungus with gamma-linolenic acid (GLA) on the fatty acid composition. Wistar rats were fed with three kinds of oil for two weeks as follows: (i) control group: corn oil; (ii) GLA group: borage oil; (iii) DGLA group: DGLA oil/safflower oil = 55:45. The DGLA concentrations in the liver, serum, and brain of the DGLA group were higher than those of the GLA oil group. We also examined the dose effect of DGLA. The DGLA levels in the liver, serum, and brain significantly increased with increasing dosage of DGLA in the diet. DGLA administration significantly increased the ratio of PGE1/PGE2 in the rat plasma. The mechanism for GLA administration to improve atopic eczema is thought to involve an increase in the concentration of DGLA metabolized from GLA, so these results suggest that the dietary effect of DGLA would be more dominant than GLA.
Subject(s)
8,11,14-Eicosatrienoic Acid/pharmacokinetics , Brain/metabolism , Dermatitis, Atopic/drug therapy , Liver/metabolism , gamma-Linolenic Acid/pharmacokinetics , 8,11,14-Eicosatrienoic Acid/administration & dosage , 8,11,14-Eicosatrienoic Acid/blood , Administration, Oral , Alprostadil/blood , Animals , Delta-5 Fatty Acid Desaturase , Dinoprostone/blood , Fatty Acid Desaturases/biosynthesis , Fatty Acid Desaturases/genetics , Linoleoyl-CoA Desaturase/biosynthesis , Linoleoyl-CoA Desaturase/genetics , Male , PPAR alpha/biosynthesis , PPAR alpha/genetics , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Rats , Rats, Wistar , Reverse Transcriptase Polymerase Chain Reaction , Sterol Regulatory Element Binding Proteins/biosynthesis , Sterol Regulatory Element Binding Proteins/genetics , gamma-Linolenic Acid/administration & dosage , gamma-Linolenic Acid/bloodABSTRACT
In this study, we examined the effects of sesamin and vegetable oil on the concentrations of polyunsaturated fatty acid (PUFA) and lipids (triacylglycerol, free cholesterol, and phospholipid), and beta-oxidation enzyme activities in the rat liver. Rats were fed a diet containing 5% (low-fat diet) or 20% (high-fat diet) salad oil (rapeseed oil: soybean oil, 7:3) with or without sesamin (0.5% w/w) for 4 wk. As a result, the concentrations of linoleic acid (LA, n-6), alpha-linolenic acid (ALA, n-3), and total PUFA in the liver increased significantly as the result of the high-fat diet. In the high-fat diet groups, sesamin administration decreased the concentrations of LA, ALA, and total PUFA to almost the same level as the low-fat diet group, while it increased the concentrations of dihomo-gamma-linolenic acid (DGLA, n-6) and arachidonic acid (AA, n-6). The activities of carnitine acyltransferase and acyl-CoA dehydrogenase in liver mitochondria were enhanced by the intake of the high-fat diet, and were further enhanced by the administration of sesamin. Peroxisomal acyl-CoA oxidase activity was also enhanced by sesamin, while it was not affected by the dietary fat level. These results suggest that sesamin suppressed the increase of hepatic PUFA concentration caused by feeding the high-fat diet through enhancing the enzyme activities of fatty acid beta-oxidation and PUFA metabolism from LA and ALA.
Subject(s)
Dietary Fats/administration & dosage , Dioxoles/administration & dosage , Fatty Acids, Unsaturated/metabolism , Lignans/administration & dosage , 8,11,14-Eicosatrienoic Acid/analysis , Acyl-CoA Dehydrogenase/metabolism , Animals , Arachidonic Acid/analysis , Carnitine Acyltransferases/metabolism , Fatty Acids, Monounsaturated , Fatty Acids, Unsaturated/analysis , Linoleic Acid/analysis , Liver/chemistry , Liver/drug effects , Male , Mitochondria, Liver/enzymology , Plant Oils/administration & dosage , Rapeseed Oil , Rats , Rats, Wistar , Soybean Oil/administration & dosage , alpha-Linolenic Acid/analysisABSTRACT
Sesamin, a lignan in sesame seeds and sesame seed oil, and capsaicin, the pungent principle of hot red pepper, affect lipid metabolism. Sesamin specifically inhibits delta5 desaturase activity in the Mortierella alpina fungus and rat liver microsomes, however, the effects of sesamin and capsaicin on mRNA expressions of delta6 and delta5 desaturases are not still clear. In this study, we investigated the effects of sesamin and capsaicin on the desaturation indexes of delta6 [(gamma-linolenic acid+dihomo-gamma-linolenic acid)/linolenic acid, (GLA+DGLA)/LA] and delta5 (arachidonic acid/DGLA, AA/DGLA) and mRNA expressions of delta6 and delta5 desaturases in rat primary cultured hepatocytes. To measure the mRNA expressions of delta6 and delta5 desaturase, hepatocytes were cultured in the presence of sesamin or capsaicin for 24 h. To investigate the delta6 or delta5 desaturation index, hepatocytes were cultured in the presence of LA or DGLA, respectively, with sesamin or capsaicin for 24 h. The fatty acid composition of the cells was measured by GLC. The mRNA expressions of delta6 and delta5 desaturases were detected by real time quantitative RT-PCR. Sesamin and capsaicin had no effect on the mRNA expressions of delta6 and delta5 desaturases in rat hepatocytes. Capsaicin had no effect on both delta6 and delta5 desaturation indexes, either. On the other hand, sesamin significantly reduced the index of delta5 desaturation but not delta6 desaturation. These results suggested that sesamin reduced the delta5 desaturation index without the changing of the delta5 desaturase mRNA level.