| 1. |
- Chen, Q, et al.
(författare)
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Hydrolysis of triacylglycerol arachidonic and linoleic acid ester bonds by human pancreatic lipase and carboxyl ester lipase
- 1989
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Ingår i: Biochimica et Biophysica Acta. - : Elsevier BV. - 0006-3002. ; 1004:3, s. 85-372
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Tidskriftsartikel (refereegranskat)abstract
- The hydrolysis of polyenoic fatty acid ester bonds with pure human colipase-dependent lipase, with carboxyl ester lipase (CEL) and with these enzymes in combination was studied, using [3H]arachidonic- and [14C]linoleic acid-labelled rat chylomicrons as a model substrate. During the hydrolysis with colipase-dependent lipase, the amount of 3H appearing in 1,2-X-diacylglycerol (DG) markedly exceeded that of 14C. When CEL was added in addition this [3H]DG was efficiently hydrolyzed. CEL alone hydrolyzed the triacylglycerol (TG) at a low rate. The hydrolysis pattern with human duodenal content was similar to that seen with colipase-dependent lipase and CEL in combination. Increasing the concentration of taurodeoxycholate (TDC) and taurocholate (TC) or of TDC alone stimulated the hydrolysis of [3H]- and [14C]TG, but increased the accumulation of labelled DG that could act as substrate for CEL. It is suggested that very-long-chain polyenoic fatty acids of DG formed during the action of the colipase-dependent lipase on TG containing these fatty acids may be a physiological substrate for CEL.
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| 2. |
- Franzen, Johan, et al.
(författare)
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Regulation of apolipoprotein A1 synthesis in lymph drained rats
- 1987
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Ingår i: Biochimica et Biophysica Acta. - : Elsevier BV. - 0006-3002. ; 918:1, s. 11-15
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Tidskriftsartikel (refereegranskat)abstract
- The effect of lymph diversion on plasma apolipoprotein A-I levels was studied. In lymph fistula rats apolipoprotein A-I levels in plasma stayed constant in spite of a loss of an equivalent of one-half plasma pool of apolipoprotein A-I per day through the lymph fistula. This indicates that synthesis of apolipoprotein A-I increases or that catabolism of apolipoprotein A-I decreases in a compensatory manner as intestinal apolipoprotein A-I is diverted. By using incorporation of [3H]leucine into newly synthesized apolipoprotein A-I it was shown that 2.6-times as much [3H]leucine was incorporated into apolipoprotein A-I in thoracic duct drained animals compared to controls. In experiments in which 125I-labeled HDL was injected intravenously into rats, it was shown that catabolism of HDL and apolipoprotein A-I was not decreased in lymph-drained rats. These data thus suggest that an increased synthesis of apolipoprotein A-I occurs when the intestinal contribution of apolipoprotein A-I diminishes. This is probably due to an increase in liver protein synthesis.
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| 3. |
- Jensen, Elmo, et al.
(författare)
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Cell density dependent uptake of chylomicron remnants in rat hepatocyte monolaayers. Effects of compactin and mevalonic acid.
- 1987
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Ingår i: Biochimica et Biophysica Acta. - : Elsevier BV. - 0006-3002. ; 917:1, s. 74-80
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Tidskriftsartikel (refereegranskat)abstract
- In rat hepatocytes cultured in lipoprotein-deficient serum, the uptake and degradation of chylomicron remnant cholesteryl ester per mg cell protein varies inversely with cell density. Compactin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme-A reductase, stimulates the uptake at all cell densities. Mevalonic acid, on the other hand, can suppress a significant part of the remnant uptake. Chylomicron remnant uptake in hepatocyte cultures can thus be influenced by factors known to regulate the apolipoprotein-BE receptor activity.
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