Elongation, desaturation, and esterification of essential fatty acids by fetal rat brain in vivo.
Tracer amounts of either [1-14C]linolenic (18:3n-3, LNA), or [1-14C]linoleic (18:2n-6, LA) acids were intracranially injected into 19- to 20-day-old rat fetuses, and the time course of the in vivo formation and esterification of their long chain polyenoic metabolites was determined for up to 20 h. A...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Elsevier
1993-12-01
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| Series: | Journal of Lipid Research |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520353517 |
| _version_ | 1818725511784824832 |
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| author | Pnina Green Ephraim Yavin |
| author_facet | Pnina Green Ephraim Yavin |
| author_sort | Pnina Green |
| collection | DOAJ |
| description | Tracer amounts of either [1-14C]linolenic (18:3n-3, LNA), or [1-14C]linoleic (18:2n-6, LA) acids were intracranially injected into 19- to 20-day-old rat fetuses, and the time course of the in vivo formation and esterification of their long chain polyenoic metabolites was determined for up to 20 h. A rapid disappearance of free LNA and LA, with apparent half-lives of 60 and 40 min, respectively, was noticed. One hour after LNA injection, 32.3% and 14.3% of the total brain radioactivity was found in the neutral glyceride (NG) and phospholipid (PL) fractions, respectively. After 20 h, PL radioactivity attained a level of 75%. Phosphatidylcholine (PC), diacylglycerol (DG), and triacylglycerol (TG) constituted 40%, 23%, and 9% of the total brain label at 1 h, and 35%, 10% and 14% at 20 h, respectively. Ethanolamine-containing PL (including plasmalogen) radioactivity accounted for about 10% up to 6 h and increased nearly 3-fold at 20 h, primarily due to an increase in the amount of labeled docosapentaenoic and docosahexaenoic acids (DHA), the elongation-desaturation products of LNA. A similar pattern of incorporation into NG and PL fraction was observed after the administration of [1-14C]LA. After 1 h, PC, DG, and TG species constituted 23%, 10%, and 23% of the total brain radioactivity, whereas after 20 h it accounted for 44%, 6%, and 10%, respectively. Although radioactivity in the ethanolamine PL also increased substantially from 4% at 1 h to 29% at 20 h, the main labeled fatty acid in this fraction was LA. Labeled arachidonic acid (AA) constituted 42.7% of the total radioactivity in phosphatidylinositol (PI) at 20 h. At this time, it comprised 12.5% and 14% of the total radioactivity in PC and ethanolamine PL, respectively, suggesting a high degree of esterification selectivity. Comparison of the total amounts of LA and LNA and their corresponding labeled AA and DHA metabolites in brain and liver after 3 and 6 h indicated that the contribution of liver metabolism to the elongation-desaturation under these conditions was negligible. One hour after intracerebral injection of [3H]DHA (22:6n-3) or [3H]AA (20:4n-6), 29.2% and 12% of total radioactivity, respectively, was found in the ethanolamine PL while 20% and 40% was incorporated in PC, respectively. PI labeling by [3H]AA was 6- to 8-fold higher than that seen in the presence of DHA. A high percent of radioactivity (26.9% and 18.2%) was found in DG and TG species. The present results indicate that the near-term fetal rat brain has the capacity to take up, convert, and selectively esterify essential fatty acids and their long-chain polyenoic derivatives into phospholipids |
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| publishDate | 1993-12-01 |
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| spelling | doaj.art-0b048e05ed4a4f23823ce4b24656a0c62022-12-21T21:31:31ZengElsevierJournal of Lipid Research0022-22751993-12-01341220992107Elongation, desaturation, and esterification of essential fatty acids by fetal rat brain in vivo.Pnina Green0Ephraim Yavin1Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel.To whom correspondence should be addressed.; Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel.Tracer amounts of either [1-14C]linolenic (18:3n-3, LNA), or [1-14C]linoleic (18:2n-6, LA) acids were intracranially injected into 19- to 20-day-old rat fetuses, and the time course of the in vivo formation and esterification of their long chain polyenoic metabolites was determined for up to 20 h. A rapid disappearance of free LNA and LA, with apparent half-lives of 60 and 40 min, respectively, was noticed. One hour after LNA injection, 32.3% and 14.3% of the total brain radioactivity was found in the neutral glyceride (NG) and phospholipid (PL) fractions, respectively. After 20 h, PL radioactivity attained a level of 75%. Phosphatidylcholine (PC), diacylglycerol (DG), and triacylglycerol (TG) constituted 40%, 23%, and 9% of the total brain label at 1 h, and 35%, 10% and 14% at 20 h, respectively. Ethanolamine-containing PL (including plasmalogen) radioactivity accounted for about 10% up to 6 h and increased nearly 3-fold at 20 h, primarily due to an increase in the amount of labeled docosapentaenoic and docosahexaenoic acids (DHA), the elongation-desaturation products of LNA. A similar pattern of incorporation into NG and PL fraction was observed after the administration of [1-14C]LA. After 1 h, PC, DG, and TG species constituted 23%, 10%, and 23% of the total brain radioactivity, whereas after 20 h it accounted for 44%, 6%, and 10%, respectively. Although radioactivity in the ethanolamine PL also increased substantially from 4% at 1 h to 29% at 20 h, the main labeled fatty acid in this fraction was LA. Labeled arachidonic acid (AA) constituted 42.7% of the total radioactivity in phosphatidylinositol (PI) at 20 h. At this time, it comprised 12.5% and 14% of the total radioactivity in PC and ethanolamine PL, respectively, suggesting a high degree of esterification selectivity. Comparison of the total amounts of LA and LNA and their corresponding labeled AA and DHA metabolites in brain and liver after 3 and 6 h indicated that the contribution of liver metabolism to the elongation-desaturation under these conditions was negligible. One hour after intracerebral injection of [3H]DHA (22:6n-3) or [3H]AA (20:4n-6), 29.2% and 12% of total radioactivity, respectively, was found in the ethanolamine PL while 20% and 40% was incorporated in PC, respectively. PI labeling by [3H]AA was 6- to 8-fold higher than that seen in the presence of DHA. A high percent of radioactivity (26.9% and 18.2%) was found in DG and TG species. The present results indicate that the near-term fetal rat brain has the capacity to take up, convert, and selectively esterify essential fatty acids and their long-chain polyenoic derivatives into phospholipidshttp://www.sciencedirect.com/science/article/pii/S0022227520353517essential fatty acidsfetal brain developmentdocosahexaenoic acidarachidonic acidelongation-desaturation |
| spellingShingle | Pnina Green Ephraim Yavin Elongation, desaturation, and esterification of essential fatty acids by fetal rat brain in vivo. Journal of Lipid Research essential fatty acids fetal brain development docosahexaenoic acid arachidonic acid elongation-desaturation |
| title | Elongation, desaturation, and esterification of essential fatty acids by fetal rat brain in vivo. |
| title_full | Elongation, desaturation, and esterification of essential fatty acids by fetal rat brain in vivo. |
| title_fullStr | Elongation, desaturation, and esterification of essential fatty acids by fetal rat brain in vivo. |
| title_full_unstemmed | Elongation, desaturation, and esterification of essential fatty acids by fetal rat brain in vivo. |
| title_short | Elongation, desaturation, and esterification of essential fatty acids by fetal rat brain in vivo. |
| title_sort | elongation desaturation and esterification of essential fatty acids by fetal rat brain in vivo |
| topic | essential fatty acids fetal brain development docosahexaenoic acid arachidonic acid elongation-desaturation |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520353517 |
| work_keys_str_mv | AT pninagreen elongationdesaturationandesterificationofessentialfattyacidsbyfetalratbraininvivo AT ephraimyavin elongationdesaturationandesterificationofessentialfattyacidsbyfetalratbraininvivo |