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The absorption of evening primrose oil and borage oil in human volunteers
Poster Presentations Monday 21 July
P37 The In Vivo Incorporation and Metabolism of [1-14C]18:3n-3 in Liver, Brain and Eyes of Fish. Gabriel Muurente t and Douglas R. Tocher2, iFacultad de Ciencias del Mar, Universidad de C~idiz, C~diz, Spain; 2NERC Unit of Aquatic Biuchemistry, Dept. of Biol. and Mol. Sciences, University of Stirling, Stirling, U.K. Accumulation of docosahexaenoic acid (DHA; 22:6n-3) in brain and eyes during development has been demonstrated in fish but it is not clear whether liver or neural tissues themselves are of greater importance in the biosynthesis of DHA from dietary 18:3n-3. In the present study, we investigated the in vivo metabolism of intraperitoneally injected [1-14C]18:3n-3 in liver, brains and eyes of young juvenile fish. Metabolism was followed over a 48h time-course in order to obtain dynamic information that could elucidate the roles of the different tissues in the biosynthesis and provision of DHA from dietary 18:3n-3. The study was performed in both a freshwater fish, rainbow trout Oncorhynchus mykiss L., and a marine fish, gilthead sea bream Sparus aurata L. to determine the effect that low or limiting ~.5-desaturase activity may have in this process. The results showed that although the sea bream incorporated more 18:3n-3 into its Iipids, metabolism of the incorporated fatty acid by desaturation and elongation was greater in the trout. In liver, the percentages of radioactivity recovered in tetraene and pentaene products were greater in trout than in sea bream although there was no difference in hexaenes. In contrast, the recovery of radioactivity in DHA was significantly greater in brain in trout compared to sea bream. In both species, the percentage of radioactivity recovered in desaturated/elongated products was much lower in liver than in brains and eyes, but that percentage increased over the 48h time-course. In trout, the highest percentages of desaturated products in brain and eye were observed after 12h and 24h, respectively. However in sea bream the highest percentages of desaturated products in the neural tissues were observed after 24-48h. Radioactivity was recovered in 24:5n-3 and 24:6n-3, intermediates in the A4-independent pathway for the synthesis of DHA, in both species, especially in the brain and eyes. In conclusion, although the results cannot eliminate a role for liver in the biosynthesis and provision of DHA for developing neural tissues in fish, they suggest that DHA can be synthesised in fish brain and eye in vivo.
EFA & Eicosanoids 1997 - Edinburgh
P38 The absorption of Evening Primrose Oil and Borage Oil in human volunteers. V d M e r w e C.F 1, v ILhee M . A ~, v d Horst, B,J i, L o u w r e n s C 2, De C o n i n g P.J 2, Joubert H.F 2 . D e p t s G a s t r o e n t e r o l o g y t , Chem P a t h o l o g y 2 M e d Unlv SA, P O M E D U N S A 0204. The absorption o f Gamma-linolenic A c i d ( G L A ) from B o r a g e Oil ( B O ) c o n t a i n i n g 2 7 % o f G L A in rats is one third the absorption o f G L A f~om Evening Primrose Oil (EPO) containing 9 % o f G L A due to different positions o f the G L A on the glycerol backbone. Aim: To investigate the absorption o f E P O and B O in humans. Materials and methods: From earlier studies done by us, it b e c a m e evident that in order to achieve detectable s e r u m peaks, subjects had to b e " p r i m e d " before. Dutch elective students v o l u n t e e r e d to take EPO and later B O for 4 w e e k s at 5 g per day. They then t o o k 12 g o f E P O after an overnight fast. During the experiment only w a t e r w a s allowed. V e n o u s b l o o d s w e r e t a k e n at 0, 2, 3, 4, and 5 hours. SLinoleic Acid (LA) and S- G L A v a l u e s w e r e determined using solid p h a s e extraction (Amino), conversion to m e t h y l esters with BF 3 and capillary gas chromatography on a Vafian 3300 instrument with a 100 meter Chrompack CPsi188 column and FID detection. After 4 w e e k s the experiment w a s repeated with 12 g o f B O after 4 w e e k s o f priming w i t h 5 g o f B O per day. S- LA, S - G L A and S-Erucic Acid (EA) values w e r e estimated for the B O g r o u p using the m e t h o d above. Results: E P O and B O seems to be absorbed equally well in humans. The difference in G L A content in both oils w a s reflected in their serum values. S e r u m G L A values after B O ingestion w a s about three times higher than after E P O ingestion. S-Erucic acid v a l u e s w e r e higher at 0 hours than at any time after B O ingestion. The a v e r a g e 0 h o u r value w a s 0.0006 mg/ml. Conclusion: The difference in fatty acid, especially GLA, u p t a k e b e t w e e n E P O and B O in laboratory animals is not found in humans. This will have to be confirmed.
P39
P40
Plasma Fatty Acid Changes in a Fasting/Refeeding Animal Model D.t~ Jenkins, LC. Campbell-Palmer, K.L. Reeves, K.J. Gaul and D.F. Horrobin. Scotia Research Institute, Kentville, Nova Scotia, Canada
ABSORPTIONANDMETABOLISMOF ORALLYFED DIGALACTOSYLDIACYLGLYCEROLIN THE RAT. Lena Andersson,MagnusBiotaand AkeNilsson,GastroenterologyDivision,Departmentof InternalMedicine, Universityof Lund, S-221 85 LUND, Sweden, Karin Bohlinder, Anders Carlsson, Scotia LipidTeknikAB, P.O. Box 6686, S*113 84 STOCKHOLM, Sweden.
The aim of our study was to investigate the effects that a fasting period may have on the levels of fatty acids when rats were maintained on a fat free diet or regular chow. One hundred and eight rats were divided into two groups of 54. One group was fed fat free 95% basal mix (Tekald, USA) and the second was fed regular chow for 2 weeks. Both groups of rats were fasted for 24 hr and then had their respective diets returned to them for a further 24 hr. Six rats from each group were sacrificed at 0, 4, 8, 12, 16, and 24 hr during the fasting period and at 4, 8, 12, 16, and 24 hr during the refeeding period. Fat free diet fasted animals had an increase in their linoleic acid (LA) levels indicating that the LA was mobilized from lipid sources within the body. Levels of gamma-linolenic acid (GLA), dihomo-glinolenic acid (DGLA), and arachidonic acid (AA) also increased. A different pattern was observed in the regular chow group. Plasma and liver fatty acid results when the regular chow rats were fasted. In plasma the LA content decreased while in the liver it remained unchanged. The GLA levels in both tissues however did increase while the amount of DGLA decreased over 24 hr., indicating an impairment in elongation. AA levels did not increase in the liver but did in the plasma during the fasting pedod. Changes in fatty acid levels during fasting indicate that there was an increased turnover of GLA througfi to AA during the first 16 hr in the plasma. It could also be concluded that mobilization of AA from other lipid sources had occurred. The lipid content of the diet and the timing of feeding both have a profound effect upon tissue fatty acid levels.
223
Digalactosyldiacylglycerol (DGalDG) and monogalactosyldiacylglycerol (MGalDG) are dominating membrane lipids of green plants. In vitro, human duodenal contents, pancreatic juice and bile salt stimulated lipase as well as guinea pig and rat pancreatic lipase related protein 2 hydrolyzed galactolipids to free fatty acids, di- and monogalactosylmonoacylglycerols and water soluble galactose-containing compounds. Here we investigated the digestion and absorption of DGalDG in the rat_[3H] DGalDG in galactolipid dispersions,and 20% soybean triacylglycerol (TG) oil -galactolipid emulsions of different concentrations were orally fed to intact and lymphatic duct cannulated rats. Chyle, gastrointestinal tract, liver and plasma were analyzed for radioactivity in different lipid classes. Recovery of [3HI was also determined in faeces. Comparison was made with an emulsion of []4C]dipalmitoyl-phosphatidytcholine (~4C DPPC), soybean TG oil and soybean PC. Only 2.3_+0.4 % of the radioactivity in chyle was found in DGalDG, more than 70 % of the radioactivity in TG, and the remaining part in glycerophospholipids. In intact rats 1.5_+0.9 % or less of radioactivity in liver and plasma was identified as DGalDG. In experiments where 120 mg PC- or galactolipidmixtures, were given the absorption of galactolipid fatty acids was less complete than PC-fatty acids, as indicated by analysis of faeces and intestinal content. We concluded that galactolipids are not absorbed intact or as reacylated monoacyl compounds.
P37 The In Vivo Incorporation and Metabolism of [1-14C]18:3n-3 in Liver, Brain and Eyes of Fish. Gabriel Muurente t and Douglas R. Tocher2, iFacultad de Ciencias del Mar, Universidad de C~idiz, C~diz, Spain; 2NERC Unit of Aquatic Biuchemistry, Dept. of Biol. and Mol. Sciences, University of Stirling, Stirling, U.K. Accumulation of docosahexaenoic acid (DHA; 22:6n-3) in brain and eyes during development has been demonstrated in fish but it is not clear whether liver or neural tissues themselves are of greater importance in the biosynthesis of DHA from dietary 18:3n-3. In the present study, we investigated the in vivo metabolism of intraperitoneally injected [1-14C]18:3n-3 in liver, brains and eyes of young juvenile fish. Metabolism was followed over a 48h time-course in order to obtain dynamic information that could elucidate the roles of the different tissues in the biosynthesis and provision of DHA from dietary 18:3n-3. The study was performed in both a freshwater fish, rainbow trout Oncorhynchus mykiss L., and a marine fish, gilthead sea bream Sparus aurata L. to determine the effect that low or limiting ~.5-desaturase activity may have in this process. The results showed that although the sea bream incorporated more 18:3n-3 into its Iipids, metabolism of the incorporated fatty acid by desaturation and elongation was greater in the trout. In liver, the percentages of radioactivity recovered in tetraene and pentaene products were greater in trout than in sea bream although there was no difference in hexaenes. In contrast, the recovery of radioactivity in DHA was significantly greater in brain in trout compared to sea bream. In both species, the percentage of radioactivity recovered in desaturated/elongated products was much lower in liver than in brains and eyes, but that percentage increased over the 48h time-course. In trout, the highest percentages of desaturated products in brain and eye were observed after 12h and 24h, respectively. However in sea bream the highest percentages of desaturated products in the neural tissues were observed after 24-48h. Radioactivity was recovered in 24:5n-3 and 24:6n-3, intermediates in the A4-independent pathway for the synthesis of DHA, in both species, especially in the brain and eyes. In conclusion, although the results cannot eliminate a role for liver in the biosynthesis and provision of DHA for developing neural tissues in fish, they suggest that DHA can be synthesised in fish brain and eye in vivo.
EFA & Eicosanoids 1997 - Edinburgh
P38 The absorption of Evening Primrose Oil and Borage Oil in human volunteers. V d M e r w e C.F 1, v ILhee M . A ~, v d Horst, B,J i, L o u w r e n s C 2, De C o n i n g P.J 2, Joubert H.F 2 . D e p t s G a s t r o e n t e r o l o g y t , Chem P a t h o l o g y 2 M e d Unlv SA, P O M E D U N S A 0204. The absorption o f Gamma-linolenic A c i d ( G L A ) from B o r a g e Oil ( B O ) c o n t a i n i n g 2 7 % o f G L A in rats is one third the absorption o f G L A f~om Evening Primrose Oil (EPO) containing 9 % o f G L A due to different positions o f the G L A on the glycerol backbone. Aim: To investigate the absorption o f E P O and B O in humans. Materials and methods: From earlier studies done by us, it b e c a m e evident that in order to achieve detectable s e r u m peaks, subjects had to b e " p r i m e d " before. Dutch elective students v o l u n t e e r e d to take EPO and later B O for 4 w e e k s at 5 g per day. They then t o o k 12 g o f E P O after an overnight fast. During the experiment only w a t e r w a s allowed. V e n o u s b l o o d s w e r e t a k e n at 0, 2, 3, 4, and 5 hours. SLinoleic Acid (LA) and S- G L A v a l u e s w e r e determined using solid p h a s e extraction (Amino), conversion to m e t h y l esters with BF 3 and capillary gas chromatography on a Vafian 3300 instrument with a 100 meter Chrompack CPsi188 column and FID detection. After 4 w e e k s the experiment w a s repeated with 12 g o f B O after 4 w e e k s o f priming w i t h 5 g o f B O per day. S- LA, S - G L A and S-Erucic Acid (EA) values w e r e estimated for the B O g r o u p using the m e t h o d above. Results: E P O and B O seems to be absorbed equally well in humans. The difference in G L A content in both oils w a s reflected in their serum values. S e r u m G L A values after B O ingestion w a s about three times higher than after E P O ingestion. S-Erucic acid v a l u e s w e r e higher at 0 hours than at any time after B O ingestion. The a v e r a g e 0 h o u r value w a s 0.0006 mg/ml. Conclusion: The difference in fatty acid, especially GLA, u p t a k e b e t w e e n E P O and B O in laboratory animals is not found in humans. This will have to be confirmed.
P39
P40
Plasma Fatty Acid Changes in a Fasting/Refeeding Animal Model D.t~ Jenkins, LC. Campbell-Palmer, K.L. Reeves, K.J. Gaul and D.F. Horrobin. Scotia Research Institute, Kentville, Nova Scotia, Canada
ABSORPTIONANDMETABOLISMOF ORALLYFED DIGALACTOSYLDIACYLGLYCEROLIN THE RAT. Lena Andersson,MagnusBiotaand AkeNilsson,GastroenterologyDivision,Departmentof InternalMedicine, Universityof Lund, S-221 85 LUND, Sweden, Karin Bohlinder, Anders Carlsson, Scotia LipidTeknikAB, P.O. Box 6686, S*113 84 STOCKHOLM, Sweden.
The aim of our study was to investigate the effects that a fasting period may have on the levels of fatty acids when rats were maintained on a fat free diet or regular chow. One hundred and eight rats were divided into two groups of 54. One group was fed fat free 95% basal mix (Tekald, USA) and the second was fed regular chow for 2 weeks. Both groups of rats were fasted for 24 hr and then had their respective diets returned to them for a further 24 hr. Six rats from each group were sacrificed at 0, 4, 8, 12, 16, and 24 hr during the fasting period and at 4, 8, 12, 16, and 24 hr during the refeeding period. Fat free diet fasted animals had an increase in their linoleic acid (LA) levels indicating that the LA was mobilized from lipid sources within the body. Levels of gamma-linolenic acid (GLA), dihomo-glinolenic acid (DGLA), and arachidonic acid (AA) also increased. A different pattern was observed in the regular chow group. Plasma and liver fatty acid results when the regular chow rats were fasted. In plasma the LA content decreased while in the liver it remained unchanged. The GLA levels in both tissues however did increase while the amount of DGLA decreased over 24 hr., indicating an impairment in elongation. AA levels did not increase in the liver but did in the plasma during the fasting pedod. Changes in fatty acid levels during fasting indicate that there was an increased turnover of GLA througfi to AA during the first 16 hr in the plasma. It could also be concluded that mobilization of AA from other lipid sources had occurred. The lipid content of the diet and the timing of feeding both have a profound effect upon tissue fatty acid levels.
223
Digalactosyldiacylglycerol (DGalDG) and monogalactosyldiacylglycerol (MGalDG) are dominating membrane lipids of green plants. In vitro, human duodenal contents, pancreatic juice and bile salt stimulated lipase as well as guinea pig and rat pancreatic lipase related protein 2 hydrolyzed galactolipids to free fatty acids, di- and monogalactosylmonoacylglycerols and water soluble galactose-containing compounds. Here we investigated the digestion and absorption of DGalDG in the rat_[3H] DGalDG in galactolipid dispersions,and 20% soybean triacylglycerol (TG) oil -galactolipid emulsions of different concentrations were orally fed to intact and lymphatic duct cannulated rats. Chyle, gastrointestinal tract, liver and plasma were analyzed for radioactivity in different lipid classes. Recovery of [3HI was also determined in faeces. Comparison was made with an emulsion of []4C]dipalmitoyl-phosphatidytcholine (~4C DPPC), soybean TG oil and soybean PC. Only 2.3_+0.4 % of the radioactivity in chyle was found in DGalDG, more than 70 % of the radioactivity in TG, and the remaining part in glycerophospholipids. In intact rats 1.5_+0.9 % or less of radioactivity in liver and plasma was identified as DGalDG. In experiments where 120 mg PC- or galactolipidmixtures, were given the absorption of galactolipid fatty acids was less complete than PC-fatty acids, as indicated by analysis of faeces and intestinal content. We concluded that galactolipids are not absorbed intact or as reacylated monoacyl compounds.