Synthesis and lymphatic transport of intestinal apolipoprotein A-IV in response to graded doses of triglyceride.
Factors regulating the intestinal synthesis and secretion of apoA-IV are incompletely understood. Although it is known that apoA-IV is stimulated by dietary lipid, it is not known whether graded doses of triglyceride elicit graded responses in apoA-IV synthesis and secretion. We used the chronic int...
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| Format: | Article |
| Language: | English |
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Elsevier
1994-07-01
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| Series: | Journal of Lipid Research |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520399594 |
| _version_ | 1818607391386632192 |
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| author | T J Kalogeris K Fukagawa P Tso |
| author_facet | T J Kalogeris K Fukagawa P Tso |
| author_sort | T J Kalogeris |
| collection | DOAJ |
| description | Factors regulating the intestinal synthesis and secretion of apoA-IV are incompletely understood. Although it is known that apoA-IV is stimulated by dietary lipid, it is not known whether graded doses of triglyceride elicit graded responses in apoA-IV synthesis and secretion. We used the chronic intestinal lymph-fistula rat to examine the effect of graded levels of intestinal triglyceride transport on secretion of apoA-IV into lymph and synthesis of apoA-IV in various regions of intestine. Rats were implanted with chronic duodenal and intestinal lymph duct cannulas and infused with lipid emulsions containing 5, 10, 20, 40, 80 mumol triolein (including [3H]triolein, 1.2 microCi), 8.7 mumol phosphatidylcholine, and 57 mumol sodium taurocholate in 3 ml phosphate-buffered saline (pH 6.4) at ml/h for 8 h. Lymph samples were collected for 1 h prior to and at 2, 4, 5, 6, 7, and 8 h after the start of lipid infusion. Lymphatic output of triglyceride, phospholipid, and apoA-IV was measured. Steady-state (8 h) content of radioactive lipid was also measured in the lumen and the wall of the gut. In separate studies rats were given infusions of either 5% glucose in saline (“fasting”) or triolein emulsion (10, 20, 40, 80 mumol/h) for 8 h after which incorporation of [3H]leucine into apoA-IV in isolated, in situ loops of duodenum, proximal jejunum, mid-distal jejunum, and terminal ileum was measured. Lipid output increased dose-dependently in response to triolein infusion, with steady-state lipid transport achieved by 5 h after start of lipid infusion. Total recovery of 3H-labeled lipid was similar for all triolein doses. Increase in lymphatic apoA-IV output lagged that of triglyceride by 3-4 h, but by 8 h showed graded increases with triolein dose. ApoA-IV synthesis (apoA-IV radioactivity immunoprecipitated by an apoA-IV monospecific antibody and expressed as % of trichloroacetic acid-precipitable [3H]leucine radioactivity) in the duodenum and proximal jejunum showed a 2-fold increase (compared with fasting) in response to 10 mumol triolein/h, but no further increase at higher doses. However, apoA-IV synthesis in mid to distal jejunum increased dose-dependently.(ABSTRACT TRUNCATED AT 400 WORDS) |
| first_indexed | 2024-12-16T14:26:00Z |
| format | Article |
| id | doaj.art-d2f9d9b36c094286bb150275893ec014 |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-16T14:26:00Z |
| publishDate | 1994-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-d2f9d9b36c094286bb150275893ec0142022-12-21T22:28:22ZengElsevierJournal of Lipid Research0022-22751994-07-0135711411151Synthesis and lymphatic transport of intestinal apolipoprotein A-IV in response to graded doses of triglyceride.T J Kalogeris0K Fukagawa1P Tso2Department of Physiology, Louisiana State University School of Medicine, Shreveport 71130.Department of Physiology, Louisiana State University School of Medicine, Shreveport 71130.Department of Physiology, Louisiana State University School of Medicine, Shreveport 71130.Factors regulating the intestinal synthesis and secretion of apoA-IV are incompletely understood. Although it is known that apoA-IV is stimulated by dietary lipid, it is not known whether graded doses of triglyceride elicit graded responses in apoA-IV synthesis and secretion. We used the chronic intestinal lymph-fistula rat to examine the effect of graded levels of intestinal triglyceride transport on secretion of apoA-IV into lymph and synthesis of apoA-IV in various regions of intestine. Rats were implanted with chronic duodenal and intestinal lymph duct cannulas and infused with lipid emulsions containing 5, 10, 20, 40, 80 mumol triolein (including [3H]triolein, 1.2 microCi), 8.7 mumol phosphatidylcholine, and 57 mumol sodium taurocholate in 3 ml phosphate-buffered saline (pH 6.4) at ml/h for 8 h. Lymph samples were collected for 1 h prior to and at 2, 4, 5, 6, 7, and 8 h after the start of lipid infusion. Lymphatic output of triglyceride, phospholipid, and apoA-IV was measured. Steady-state (8 h) content of radioactive lipid was also measured in the lumen and the wall of the gut. In separate studies rats were given infusions of either 5% glucose in saline (“fasting”) or triolein emulsion (10, 20, 40, 80 mumol/h) for 8 h after which incorporation of [3H]leucine into apoA-IV in isolated, in situ loops of duodenum, proximal jejunum, mid-distal jejunum, and terminal ileum was measured. Lipid output increased dose-dependently in response to triolein infusion, with steady-state lipid transport achieved by 5 h after start of lipid infusion. Total recovery of 3H-labeled lipid was similar for all triolein doses. Increase in lymphatic apoA-IV output lagged that of triglyceride by 3-4 h, but by 8 h showed graded increases with triolein dose. ApoA-IV synthesis (apoA-IV radioactivity immunoprecipitated by an apoA-IV monospecific antibody and expressed as % of trichloroacetic acid-precipitable [3H]leucine radioactivity) in the duodenum and proximal jejunum showed a 2-fold increase (compared with fasting) in response to 10 mumol triolein/h, but no further increase at higher doses. However, apoA-IV synthesis in mid to distal jejunum increased dose-dependently.(ABSTRACT TRUNCATED AT 400 WORDS)http://www.sciencedirect.com/science/article/pii/S0022227520399594 |
| spellingShingle | T J Kalogeris K Fukagawa P Tso Synthesis and lymphatic transport of intestinal apolipoprotein A-IV in response to graded doses of triglyceride. Journal of Lipid Research |
| title | Synthesis and lymphatic transport of intestinal apolipoprotein A-IV in response to graded doses of triglyceride. |
| title_full | Synthesis and lymphatic transport of intestinal apolipoprotein A-IV in response to graded doses of triglyceride. |
| title_fullStr | Synthesis and lymphatic transport of intestinal apolipoprotein A-IV in response to graded doses of triglyceride. |
| title_full_unstemmed | Synthesis and lymphatic transport of intestinal apolipoprotein A-IV in response to graded doses of triglyceride. |
| title_short | Synthesis and lymphatic transport of intestinal apolipoprotein A-IV in response to graded doses of triglyceride. |
| title_sort | synthesis and lymphatic transport of intestinal apolipoprotein a iv in response to graded doses of triglyceride |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520399594 |
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