Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LIPOPROTEIN LIPASE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,423 records · Page 79Linked to original sources
PubMed1996

Short-term effects of a high-sucrose diet on plasma lipid, lipoprotein cholesterol, tissue lipoprotein lipase and hepatic triglyceride lipase in rats.

Short-term (2 weeks) effects of a high-sucrose diet on plasma lipids, lipoproteins, tissue lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) activities were investigated in rats. Three days of sucrose feeding significantly increased plasma TG (42 +/- 3 mg/dl vs. 56 +/- 2 mg/dl, p = 0.032), while TC increased significantly after 10 days of the diet (50 +/- 2 mg/dl vs. 62 +/- 2 mg/dl, p = 0.0001). HDL-C increased significantly after 3 days of sucrose feeding (36.2 +/- 0.9 mg/dl vs. 42.4 +/- 2.7 mg/dl, p = 0.011). Although LDL-C tended to decrease on days 3, 7 and 10, these changes were not significant. The plasma glucose level did not change during the study. Increased LPL activity in adipose tissue and decreased enzyme activities in skeletal and heart muscles were observed. Adipose tissue LPL returned to the baseline value after 14 days of the diet treatment, while LPL in skeletal and heart muscles remained at the decreased level. HTGL and HTGL/total liver lipase activities were significantly increased after 14 days of the diet. The different responses of lipase activities in various tissues may help to regulate serum lipid and lipoprotein levels in sucrose-fed rats.

Adipose Tissue↗
PubMed2001

Lipoprotein lipase and lipogenic enzyme activities in adipose tissue from rats fed different lipid sources.

This work was designed to study the effect of different lipid sources on the activities of lipoprotein lipase and lipogenic enzymes in adipose tissue from rats fed ad libitum or energy-controlled diets. Male Wistar rats were fed diets containing 40% of energy as fat (olive oil, sunflower oil, palm oil or beef tallow), for 4 wk. Under ad libitum feeding no differences were found among dietary fat groups in final body weight, adipose tissue weights and total body fat. Under energy-controlled feeding, despite isoenergetic intake, rats fed the beef tallow diet gained significantly less weight than rats fed the other three diets. Beef tallow fed rats showed the lowest values for adipose tissue weights and total body fat. When rats had free access to food no effect of dietary lipid source on lipogenic enzyme activities was found. In contrast, under energy-controlled feeding rats fed the beef tallow diet showed significantly higher activities of glucose-6-phosphate dehydrogenase and fatty acid synthase than rats fed the other three diets. Heparin-releasable lipoprotein lipase activity in perirenal and subcutaneous adipose tissues was not different among rats fed olive oil, safflower oil, palm oil or beef tallow. When comparing both adipose tissue anatomical locations, significantly higher activities were found in subcutaneous than in perirenal fat pad independently of dietary fat. In conclusion, under our experimental protocol, lipogenesis in rat adipose tissue does not seem to be affected by dietary fat type.

Acetyl-CoA Carboxylase↗
PubMed1995

A lipoprotein lipase mutation (Asn291Ser) is associated with reduced HDL cholesterol levels in premature atherosclerosis.

A reduction of high density lipoprotein cholesterol (HDC) is recognized as an important risk factor for coronary artery disease (CAD). We now show in approximately 1 in 20 males with proven atherosclerosis that an Asn291Ser mutation in the human lipoprotein lipase (LPL) gene is associated with significantly reduced HDL levels (P = 0.001) and results in a significant decrease in LPL catalytic activity (P < 0.0009). The relative frequency of this mutation increases in those patients with lower HDL cholesterol levels. In vitro mutagenesis and expression studies confirm that this change is associated with a significant reduction in LPL activity. Our data support the relationship between LPL activity and HDL-C levels, and suggest that a specific LPL mutation may be a factor in the development of atherosclerosis.

Adult↗
PubMed2002

Very low density lipoprotein (VLDL) receptor-deficient mice have reduced lipoprotein lipase activity. Possible causes of hypertriglyceridemia and reduced body mass with VLDL receptor deficiency.

Although very low density lipoprotein (VLDL) receptor (VLDLr) knockout mice have been reported to have no lipoprotein abnormalities, they develop less adipose tissue than control mice when fed a high calorie diet. Mice that are deficient in adipose tissue expression of lipoprotein lipase (LpL) also have less fat, but only when crossed with ob/ob mice. We hypothesized that the VLDLr, a protein that will bind and transport LpL, is required for optimal LpL actions in vivo and that hypertriglyceridemia due to VLDLr deficiency is exacerbated by either LpL deficiency or VLDL overproduction. Fasted VLDLr knockout (VLDLr0) mice were more hypertriglyceridemic than controls (2-fold greater triglyceride levels). The hypertriglyceridemia due to VLDLr0 was even more evident when VLDLr0 mice were crossed with heterozygous LpL-deficient (LpL1) and human apolipoprotein B (apoB) transgenic mice. This was due to an increase in apoB48-containing VLDL. [(3)H]VLDL turnover studies showed that VLDL-triglyceride clearance in VLDLr0/LpL1 mice was impaired by 50% compared with LpL1 mice. VLDLr0/LpL1 mice had less LpL activity in postheparin plasma, heart, and skeletal muscle. Infection of mice with an adenovirus-expressing receptor-associated protein, an inhibitor of the VLDLr, reduced LpL activity in wild type but not VLDLr0 mice. Therefore, the VLDLr is required for normal LpL regulation in vivo, and the disruption of VLDLr results in hypertriglyceridemia associated with decreased LpL activity.

Adipose Tissue↗
PubMed1998

Species differences in substrate specificity of lipoprotein lipase purified from chickens and rats.

Kinetic parameters of chicken and rat lipoprotein lipase (LPL) were determined in the incubation in vitro with various monoacid triacylglycerol emulsion and plasma lipoproteins. In rat- and chicken-LPL there is an inverse relationship between the hydrolytic rate by both LPL and the increased acyl-chain unsaturation of monoacid triacylglycerol; C18:1>C18:2>C18:3. The rat LPL catalyzed hydrolysis of saturated monoacid triaclyglycerol increased with an increase of chain length as C16>C14>C12, whereas in chicken LPL hydrolytic rate of C12 was higher than C14 and C16 triaclyglycerol. Vmax of rat- and chicken-LPL for chylomicron and VLDL were higher but apparent Km for those were lower than other lipoproteins. In chicken, Vmax and apparent Km of LPL for VLDL were almost the same as those for chylomicron, whereas in rat, Vmax of LPL for VLDL was twice that of chylomicron with the same apparent Km. The chicken and rat VLDL with different particle size prepared by Bio-Gel A50 gel chromatography were similarly hydrolyzed by LPL, while the hydrolysis of small chicken-chylomicron particles was inclined to be higher than that of the large particles. These results show species differences between chickens and rats in the substrate specificity of LPL.

Animals↗
PubMed1987

Exercise acutely increases high density lipoprotein-cholesterol and lipoprotein lipase activity in trained and untrained men.

We studied the effects of a single exercise session on lipid and lipoprotein concentrations and on postheparin plasma lipoprotein lipase (LPLA) and hepatic triglyceride hydrolase activities (HTGLA) in 11 trained (T) and ten untrained (UT) men. Subjects exercised on a bicycle ergometer at 80% of their maximal heart rate for one (UT) or two hours (T). Blood samples were drawn 24 hours before and at ten minutes and 24, 48, and 72 hours after exercise. Values were analyzed before and after adjustment for estimated changes in plasma volume (PV). High density lipoprotein cholesterol (HDL-C) increased 2 +/- 4 mg/dL in T (P less than 0.05) and 1 +/- 2 mg/dL in UT subjects beginning 48 hours after exercise. This increase was magnified by adjusting for the 5% to 8% postexercise expansion of PV. The increase in HDL in the T subjects was produced by increases in the HDL2-C subfraction (+3 +/- 4 mg/dL, P less than 0.05) whereas HDL3 increased in the UT men (+2 +/- 3 mg/dL, P less than 0.05). LPLA did not change in either subject group when estimated PV changes were ignored but increased 11% (P less than 0.05) at 24 hours after exercise when PV was considered. HTGLA was 11% below baseline in the UT men 24 to 72 hours after exercise (P less than 0.05) but showed no change in either subject group after adjustment for PV. These results demonstrate that exercise acutely increases HDL levels by raising the HDL2 subfraction in T and the HDL3 subfraction in UT men.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The fatty liver dystrophy (fld) mutation. A new mutant mouse with a developmental abnormality in triglyceride metabolism and associated tissue-specific defects in lipoprotein lipase and hepatic lipase activities.

An autosomal recessive mutation, termed fatty liver dystrophy (fld), can be identified in neonatal mice by their enlarged and fatty liver (Sweet, H. O., Birkenmeier, E. H., and Davisson, M. T. (1988) Mouse News Letter 81, 69). We have examined the underlying metabolic abnormalities in fld/fld mice from postnatal days 3-40. Serum and hepatic triglyceride levels were elevated 5-fold in suckling fld/fld mice compared to their +/? littermates but abruptly resolved at the suckling/weaning transition. Blot hybridization analysis of liver and intestinal RNAs revealed a liver-specific increase in apolipoprotein (apo) A-IV and C-II mRNA concentrations (100- and 6-fold, respectively) that was limited to the suckling and early weaning stages in fld/fld mice. Resolution of these differences during the weaning period could not be delayed by prolonging suckling to the 20th postnatal day nor could the mutant phenotype be elicited in young adult animals with a high fat diet. Lipoprotein lipase (LPL) activity was reduced 16-fold in the white adipose tissue of fld/fld mice until the onset of weaning. Heart activity was decreased less than 2-fold, but there were no deficits in brown adipose tissue or liver. Hepatic lipase (HL) mRNA levels and activity were significantly reduced in fld/fld livers and sera, respectively, during the suckling period. Mapping studies show the fld locus to be distinct from loci encoding LPL, HL, and apoA-IV, and those responsible for the combined lipase deficiencies in cld/cld and W/Wv mice. These data suggest that the fld mutation is associated with developmentally programmed tissue-specific defects in the neonatal expression of LPL and HL activities and provide evidence for a new regulatory locus which affects these lipase activities. This mutation could serve as a useful model for (i) analyzing the homeostatic mechanisms controlling lipid metabolism in newborn mice and (ii) understanding and treating certain inborn errors in human triglyceride metabolism.

Adipose Tissue↗
PubMed1975

Effects of apolipoproteins on lipoprotein lipase activity of human adipose tissue.

The effect of apolipoproteins isolated from HDL and VLDL on the activity of lipoprotein lipase (LPL) of adipose tissue was studied. The CII apoprotein was found to activate LPL. This activation was strongly inhibited by CI, AI (apo-Lp-Gln I), and the arginine-rich apoprotein, whereas AII and CIII exhibited a considerably lower inhibitor effect.

Adipose Tissue↗
PubMed1995

Relation between insulin resistance, hyperinsulinemia, postheparin plasma lipoprotein lipase activity, and postprandial lipemia.

We examined the relation between insulin resistance, plasma glucose and insulin responses to meals, lipoprotein lipase (LPL) activity, and postprandial lipemia in a population of 37 healthy nondiabetic individuals. Plasma glucose and insulin concentrations were determined at frequent intervals from 8 AM through midnight (breakfast at 8 AM and lunch at noon); resistance to insulin-mediated glucose disposal was determined by measuring the steady-state plasma glucose (SSPG) concentration at the end of a 180-minute infusion of glucose, insulin, and somatostatin; LPL activity was quantified in postheparin plasma; and postprandial concentrations of triglyceride (TG)-rich lipoproteins were assessed by measuring the TG and retinyl palmitate content in plasma and the Svedberg flotation index (Sf) > 400 and Sf 20 to 400 lipoprotein fractions. Significant simple correlation coefficients were found between various estimates of postprandial lipemia and SSPG (r = .38 to .68), daylong insulin response (r = .37 to .58), daylong glucose response (r = .10 to .39), and LPL activity (r = -.08 to -.58). However, when multiple regression analysis was performed, only SSPG remained independently associated with both postprandial TG and retinyl palmitate concentrations. These data provide evidence that insulin resistance plays an important role in regulating the postprandial concentration of TG-rich lipoproteins, including those of intestinal origin.

Adult↗
PubMed1986

Regulation of lipoprotein lipase synthesis and 3T3-L1 adipocyte metabolism by recombinant interleukin 1.

When fully differentiated 3T3-L1 adipocytes were exposed to purified, recombinant murine interleukin 1 (rIL-1), a dose-dependent suppression of lipoprotein lipase activity was observed. The loss of activity reached a maximum of 60-70% of control and appeared to be due to an effect on the synthesis of the enzyme as judged by a suppression of the ability to incorporate [35S]methionine into immunoprecipitable lipoprotein lipase. There was no general effect on protein synthesis as determined by radiolabel incorporation into acid precipitable protein; however, after a 17 h exposure of the 3T3-L1 cells to recombinant interleukin 1, the synthesis of two proteins (molecular weights, 19,400 and 165,000 daltons) was enhanced several-fold. When the effect of Il-1 on the major metabolic pathways of the adipocyte was investigated, lipolysis as measured by glycerol release from the cells was markedly enhanced after a 17 h incubation with the hormone, while no effect was observed on de novo fatty acid synthesis. These effects on the metabolism of the adipocytes occur at concentration on a basis of molecules per cell, similar (only a 3-fold difference) to those required for stimulation of [3H]thymidine incorporation into mouse thymocyte DNA, suggesting that IL-1 may be a physiologically significant effector of adipocyte metabolism.

Adipose Tissue↗
PubMed1977

[The effects of a heterologous antibody against a crude lipoprotein lipase fraction in mice].

The antigens contained in a crude lipoprotein-lipase fraction from the Rabbit adipose tissue have no effect on Mice, even after daily injections for several months. But they induce an immune reaction in Sheep, allowing one to produce several immune sera with a high physiological activity, without any specific barrier between Rabbit and Mouse. After total absorption of these immune sera by normal Rabbit serum, the remaining antibodies have an activity against esterasic lipoproteins. Small doses of these antibodies induce in Mice marked hyperplastic and degenerative reactions of the adipose tissue and an extensive lysis of the pancreas. A correlative high lymphocytic activation, producing B and T immunoblasts, is induced.

Adipose Tissue↗
PubMed1999

Lipid and lipoprotein analysis of cats with lipoprotein lipase deficiency.

BACKGROUND: We have previously described a colony of domestic cats with a naturally occurring mutation in the lipoprotein lipase (LPL) gene. We have now further characterized cats homozygous for LPL deficiency (LPL -/-, homozygotes), and have contrasted these with heterozygotes (LPL +/-) and normal cats (LPL +/+). MATERIALS AND METHODS: Density gradient ultracentrifugation with subsequent lipid analysis, agarose and polyacrylamide gel electrophoresis was used to examine detailed liproprotein differences between the genotypes. Oral fat loading studies and breast milk fatty acid analysis were also performed to further characterize the phenotypic expression of LPL deficiency in this model system. RESULTS: Several lipid abnormalities associated with homozygosity for LPL deficiency were evident. Triglyceride-rich lipoprotein-triglycerides (TRL-TG) and cholesterol (TRL-C) were higher (TRL-TG 2.09 +/- 1.14 vs. 0.15 +/- 0.04 mmol L-1, P < 0.001; TRL-C 0.42 +/- 0.30 vs. 0.11 +/- 0.16 mmol L-1, P < 0.05) in male -/- than in male +/+ cats, as was HDL-cholesterol (HDL-C, 1.75 +/- 0.24 vs. 1.41 +/- 0.14 mmol L-1, P < 0.05). LDL-C levels were lower in homozygous cats than in control cats, similar to what is seen in human LPL deficiency. Oral fat loading studies revealed that homozygous cats have a marked reduced ability to clear plasma TGs in terms of peak time (7 h vs. 3 h), peak height (9.36 vs. 1.1 mmol L-1), area under the TG clearance curve (AUC, 280.3 vs. 2.2 h mmol L-1) and time to return to baseline. Fasting lipid and lipoprotein levels were not significantly different between heterozygous and normal cats. However, oral fat loading in heterozygotes revealed an intermediate phenotype (peak of 2.35 mmol L-1 at 5 h, AUC 13.1 h mmol L-1), highlighting the impaired TG clearance in these animals. CONCLUSION: Thus, LPL deficiency in the cat results in a lipid and lipoprotein phenotype that predominantly parallels human LPL deficiency, further validating the use of these animals in studies on the pathobiology of LPL.

Animals↗
PubMed1994

Expression of lipoprotein lipase during differentiation of cultured L6 muscle cells.

The presence of lipoprotein lipase (LPL) in L6 muscle cells is equivocal. Analysis of a 21-day time course indicates that these cells express both LPL activity and mRNA. Lipase activity peaked at 4 days after plating and decreased to a nadir at day 21 after plating. Characterization of lipase activity at 4 and 19 days after plating, corresponding to myoblasts and myotubes, respectively, indicated that most of the enzyme activity had the properties of LPL, including an alkaline pH optimum, a serum requirement, and inhibition by NaCl. LPL mRNA expression peaked at 7 days after plating and fell slightly (24%) at day 21. The primary LPL mRNA species in these cells is 3.7 kb in length. Lipase activity and LPL mRNA were highly correlated during the nine course (r = +0.82), suggesting transcriptional regulation of the enzyme. These data clearly demonstrate that L6 cells express LPL during differentiation.

Animals↗
PubMed2002

Increased expression of lipoprotein lipase in transgenic rabbits does not lead to abnormalities in skeletal and heart muscles.

Lipoprotein lipase (LPL) plays an important role in plasma lipoprotein metabolism and the uptake of free fatty acid in muscle. Previous studies using transgenic mice showed that increased LPL leads to myopathies, but these results were controversial. To examine this hypothesis, we studied LPL transgenic rabbits, and our results refute the suggested role of LPL in the pathogenesis of myopathies.

Animals↗
PubMed1994

A novel missense mutation in the C-terminal domain of lipoprotein lipase (Glu410-->Val) leads to enzyme inactivation and familial chylomicronemia.

Lipoprotein lipase (LPL) is a complex enzyme consisting of multiple functional domains essential for the initial hydrolysis of triglycerides present in plasma lipoproteins. Previous studies have localized the catalytic domain of LPL, responsible for the hydrolytic function of the enzyme, to the N-terminus whereas the C-terminal end may play a role in lipid and heparin binding. To date, most described missense mutations resulting in a nonfunctional LPL have been located in the N-terminal region of the enzyme. In this manuscript we describe the defect in the LPL gene of a patient with triglycerides ranging from normal to 12,000 mg/dl, low LPL mass, and no LPL activity in post-heparin plasma. Sequencing of patient PCR-amplified DNA identified two separate mutations in the C-terminal domain of LPL: an A-->T transversion at nucleotide 1484 resulting in a Glu410-->Val substitution and a C-->G mutation at position 1595 that introduces a premature stop codon at position 447. Digestion with MaeIII and MnII established that the patient is a true homozygote for both mutations. In order to investigate the functional significance of these defects, mutant enzymes containing either the Val410 or the Ter447 mutations as well as both Val410 and Ter447, were expressed in vitro. Compared to the wild-type enzyme, LPL447 demonstrated a moderate reduction of specific activity using triolein (70% of normal) and tributyrin (74% of normal) substrates, while LPL410 had a significant (11% and 23% of normal) reduction of the normal lipase and esterase specific activities, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1997

The lipolysis of chylomicrons derived from different dietary fats by lipoprotein lipase in vitro.

The lipolysis of chylomicrons derived from palm, olive, corn or fish oil (enriched in saturated, monounsaturated, n - 6 polyunsaturated and n - 3 polyunsaturated fatty acids, respectively) by rat post-heparin lipoprotein lipase in vitro was compared by measuring the release of [3H]oleate from their triacylglycerol. Chylomicrons derived from corn oil were lipolysed more rapidly than the other types in the first 20 min of the reaction, but after 120 min the total amount of triacylglycerol hydrolysed was similar with all types of chylomicrons used. The rate of lipolysis of the different types of chylomicrons also showed different dependencies on the substrate concentration. The highest Vmax values were obtained when the chylomicrons were derived from olive and corn oil and the lowest when they were derived from palm oil, while olive oil chylomicrons gave the highest Km and palm oil chylomicrons the lowest. These results indicate that differential metabolism of chylomicrons of different fatty acid composition by lipoprotein lipase may play a part in the differential rates of clearance from the blood of lipid of dietary origin demonstrated in earlier work from our laboratory.

Animals↗