UMLS:C0020473 - FACTA Search

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Query: UMLS:C0020473 (hyperlipidemia)
15,891 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study was conducted to examine whether nitric oxide regulates lipid metabolism. In Experiment 1, rats were fed for 5 wk diets with or without 0.2 g/kg L-N-nitroarginine (L-NNA), a specific inhibitor of nitric oxide synthase, that were or were not supplemented with 40 g/kg L-arginine. Rats fed L-NNA had significantly higher concentrations of serum triglyceride and total cholesterol, lower concentrations of serum nitrate, and a lower ratio of HDL-cholesterol to total cholesterol than rats fed the basal diet. These alterations were suppressed by supplementing L-arginine to the L-NNA-containing diet. In Experiment 2, rats were fed diets with or without 0.2 g/kg L-NNA. Dietary L-NNA elevated serum concentrations of free fatty acids without affecting those of ketone bodies. L-NNA lowered the activity of hepatic carnitine palmitoyltransferase, the rate-limiting enzyme of fatty acid oxidation, but did not affect activities of hepatic glucose-6-phosphate dehydrogenase and fatty acid synthase which are lipogenic enzymes. These results suggest that the lower nitric oxide level in rats fed L-NNA leads to hyperlipidemia and that the elevation in serum triglyceride might be due to reduced fatty acid oxidation.
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PMID:Feeding rats the nitric oxide synthase inhibitor, L-N(omega)nitroarginine, elevates serum triglyceride and cholesterol and lowers hepatic fatty acid oxidation. 885 18

Glucose stabilizes the mRNA for human fatty acid synthase (FAS), an enzyme relevant to diverse human disorders, including hyperlipidemia, obesity, and malignancy. To determine the underlying mechanisms, RNA gel mobility shift assays were used to demonstrate that human Hep G2 cells contain a cytoplasmic factor that binds specifically to the 3'-terminus of the human FAS mRNA. D-Glucose increased RNA-binding activity by 2.02-fold (P = 0.0033), with activity peaking 3 h after glucose feeding. Boiling or treatment of extracts with proteinase K abolished binding. Ultraviolet cross-linking of the FAS mRNA-binding factor followed by SDS-PAGE resolved a proteinase K-sensitive band with an apparent molecular mass of 178 +/- 7 kDa. The protein was purified to homogeneity using nondenaturing polyacrylamide gels as an affinity matrix. Acid phosphatase treatment of the protein prevented binding to the FAS mRNA, but binding activity was unaffected by modification of sulfhydryl groups and was not Mg2+ or Ca2+ dependent. Deletion and RNase T1 mapping localized the binding site of the protein to 37 nucleotides characterized by the repetitive motif ACCCC and found within the first 65 bases of the 3'-UTR. Hybridization of the FAS transcript with an oligonucleotide antisense to this sequence abolished binding. These findings indicate that a 178-kDa glucose-inducible phosphoprotein binds to an (ACCCC)n-containing sequence in the 3'-UTR of the FAS mRNA within the same time frame that glucose stabilizes the FAS message. This protein may participate in the posttranscriptional control of FAS gene expression.
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PMID:Properties and purification of a glucose-inducible human fatty acid synthase mRNA-binding protein. 957 16

The aim of this study was to evaluate the chronic effects of a short-chain fructo-oligosaccharide (FOS)-containing diet on plasma lipids and the activity of fatty acid synthase (FAS) in insulin-resistant rats. Normal male Sprague-Dawley rats, 5 wk old, were randomly assigned to two groups and fed either a sucrose-rich diet (S, 575 g sucrose /kg diet and 140 g lipids/kg diet) or a sucrose-rich diet supplemented with 10 g/100 g short-chain fructo-oligosaccharides (S/FOS). A third reference group (R) was fed a standard nonpurified diet (g/kg, 575 g starch, 50 g fat). After 3 wk the sucrose-fed rats (compared with the R group) were characterized by the following: 1) higher insulin responses after a glucose challenge (P < 0.05); 2) heavier liver (P < 0.001) and retroperitoneal adipose tissue (P < 0.01); 3) hypertriglyceridemia (P < 0.0001) and higher plasma free fatty acids (P < 0.0001); and 4) higher fatty acid synthase activity in the liver but a low activity in the adipose tissue (P < 0.001). The addition of FOS to the diet resulted in 11% lower liver weight than in the S group (P < 0.05) and tended to result in lower adipose tissue weight (P < 0.11). Plasma triglycerides and plasma free fatty acids were lower in S/FOS- than in S-fed rats (P < 0.05). Chylomicrons + VLDL, and intermediate density lipoprotein (IDL) concentrations did not differ between groups, nor was plasma cholesterol influenced by diet. Hepatic FAS activity was lower in S/FOS-fed rats than in the S-fed rats (P < 0.05). In adipose tissue, however, this activity tended to be greater in rats fed S/FOS than in rats fed the S diet (P < 0.07). In conclusion, in a rat model of diet-induced (57.5% sucrose and 14% lipids) insulin resistance, the addition of short-chain FOS prevented some lipid disorders, lowered fatty acid synthase activity in the liver and tended to raise this activity in the adipose tissue. Short-chain FOS, in addition to being a nondigestible sweetener with good bulking capacity, might be useful in the treatment of insulin resistance and hyperlipidemia.
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PMID:Plasma lipids and fatty acid synthase activity are regulated by short-chain fructo-oligosaccharides in sucrose-fed insulin-resistant rats. 968 45

Fibrate derivatives are commonly used to treat hyperlipidaemia; however, the mechanism of the antilipidaemic action of these drugs is still unknown. The effect of clofibrate (fibrate derivative) administration for 14 days on lipogenesis and on malic enzyme (EC 1.1.1.40) and fatty acid synthase (EC 2.3.1.85) gene expression in brown and white adipose tissues and in the liver was examined in rats. The rate of brown adipose tissue lipogenesis in the clofibrate-treated animals was significantly lower than that of the control rats. The rate of liver and white adipose tissue lipogenesis was not affected significantly by clofibrate. In brown adipose tissue, the drug treatment resulted in a depression of fatty acid synthase and malic enzyme mRNA levels. The fatty acid synthase mRNA level did not change significantly in the liver, whereas the malic enzyme mRNA level increased approximately 6-fold in this organ after clofibrate treatment. The malic enzyme mRNA level in white adipose tissue increased about 2-fold, while the fatty acid synthase mRNA level was unchanged after clofibrate feeding. The results presented in this paper provide further evidence that the hypolipidaemia caused by treatment of rats with clofibrate cannot be related to the inhibition of fatty acid synthesis in the liver and white adipose tissue. These data also indicate that clofibrate exhibits tissue specificity.
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PMID:Tissue-specific effect of clofibrate on rat lipogenic enzyme gene expression. 1033 10

Hyperlipidemia may complicate the use of HIV protease inhibitors (PIs) in AIDS therapy. To determine the cause of hyperlipidemia, the effect of PIs on lipid metabolism was examined with HepG2 liver cells and AKR/J mice. In HepG2 cells, the PIs ABT-378, nelfinavir, ritonavir, and saquinavir stimulated triglyceride synthesis; ritonavir increased cholesterol synthesis; and amprenavir and indinavir had no effect. Moreover, nelfinavir increased mRNA expression of diacylglycerol acyltransferase and fatty acid synthase. The retinoid X receptor agonist LG100268, but not the antagonist LG100754, further increased PI-stimulated triglyceride synthesis and mRNA expression of fatty acid synthase in vitro. In fed mice, nelfinavir or ritonavir did not affect serum glucose and cholesterol, whereas triglyceride and fatty acids increased 57% to 108%. In fasted mice, ritonavir increased serum glucose by 29%, cholesterol by 40%, and triglyceride by 99%, whereas nelfinavir had no effect, suggesting these PIs have different effects on metabolism. Consistent with the in vitro results, nelfinavir and ritonavir increased triglyceride 2- to 3-fold in fasted mice injected with Triton WR-1339, an inhibitor of triglyceride clearance. We propose that PI-associated hyperlipidemia is due to increased hepatic triglyceride synthesis and suggest that retinoids or meal restriction influences the effects of select PIs on lipid metabolism.
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PMID:HIV protease inhibitors stimulate hepatic triglyceride synthesis. 1111 63

Several nondigestible but fermentable dietary carbohydrates are able to regulate lipemia and triglyceridemia in both humans and animals. The mechanism of their serum lipid-lowering effect remains to be elucidated. Oligofructose, which is a mixture of nondigestible and fermentable fructans, can decrease triacylglycerol in VLDL when given to rats. The triacylglycerol-lowering action of oligofructose is due to a reduction of de novo fatty acid synthesis in the liver through inhibition of all lipogenic enzymes, namely acetyl-CoA carboxylase (EC 6.4.1.2), fatty acid synthase, malic enzyme (EC 1.1.1.40), ATP citrate lyase (EC 4.1.3.8), and glucose-6-phosphate dehydrogenase (EC 1.1.1.49). Our results suggest that oligofructose decreases lipogenic enzyme gene expression. Postprandial insulin and glucose concentrations are low in the serum of oligofructose-fed animals and this could explain, at least partially, the metabolic effect of oligofructose. Moreover, some events occurring in the gastrointestinal tract after oligofructose feeding could be involved in the antilipogenic effect of this fructan: the production of propionate through fermentation, a modulation of the intestinal production of incretins (namely glucose-dependent insulinotropic peptide and glucagon-like peptide-1), or the modification of the availability of digestible carbohydrates. Recent studies showed that the hypotriglyceridemic effect of fructans also occurs in humans.
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PMID:Effects of fructans-type prebiotics on lipid metabolism. 1115 57

Hyperlipidemia is a common occurance in patients with chronic renal failure (CRF) and has been the subject of many clinical and experimental studies. Despite this, the role of lipogenesis in the development of hyperlipidemia is still obscure. The present study is based on a rat model of CRF involving a two-stage subtotal nephrectomy. In this study, we measured the activity of fatty acid synthase (FAS). This is the rate-limiting enzyme of lipogenesis and is present in liver and white adipose tissue (WAT). Using isotopic methods, we also determined the rate of lipogenesis in vivo in liver and WAT. In both liver and WAT, the results of the analyses were similar. In the uremic rats, there was a tendency for the FAS activity to rise. However, the difference was not statistically significant. Furthermore, there was no increase in the rate of lipogenesis in vivo in either tissue. In summary, the results of our study confirm the thesis that lipogenesis does not play a role in the development of hypertriglyceridemia seen in an experimental CRF in rats.
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PMID:Lipogenesis in experimental chronic renal failure in rats. 1172 8

Nephrotic syndrome (NS) is characterized by the presence of proteinuria and hyperlipidemia. However, ingestion of soy protein has a hypolipidemic effect. The present study was designed to determine whether the ingestion of a 20% soy protein diet regulates the expression of hepatic sterol regulatory element binding protein (SREBP)-1, fatty acid synthase (FAS), malic enzyme, beta-hydroxy-beta-methylglutaryl-CoA (HMG-CoA) reductase (r) and synthase (s), and LDL receptor (r), and to assess whether soy protein improves lipid and renal abnormalities in rats with chronic NS. Male Wistar rats were injected with vehicle or with puromycin aminonucleoside to induce NS and were fed either 20% casein or soy protein diets for 64 d. NS rats fed 20% soy protein had improved creatinine clearance and reduced proteinuria, hypercholesterolemia, hypertriglyceridemia, as well as VLDL-triglycerides and LDL cholesterol compared with NS rats fed the 20% casein diet. In addition, the soy protein diet decreased the incidence of glomerular sclerosis, and proinflammatory cytokines in kidney. Ingestion of the soy protein diet by control rats reduced the gene expression of SREBP-1, malic enzyme, FAS and increased HMG-CoAr, HMG-CoAs and LDLr. However, NS rats fed either casein or soy protein diets had low insulin concentrations with reductions in SREBP-1, FAS and malic enzyme expression compared with control rats fed the casein diet. NS rats fed the soy diet also had lower HMG-CoAr and LDLr mRNA levels than NS rats fed casein. In conclusion, the beneficial effects of soy protein on lipid metabolism are modulated in part by SREBP-1. However, in NS rats, the benefit may be through a direct effect of this protein on kidney rather than mediated by changes in expression of hepatic lipid metabolism genes.
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PMID:A soy protein diet alters hepatic lipid metabolism gene expression and reduces serum lipids and renal fibrogenic cytokines in rats with chronic nephrotic syndrome. 1222 Dec 9

Hypertriglyceridemia associated with chronic renal failure (CRF) and elevated plasma concentration of very-low-density lipoprotein (VLDL) are thought to be a consequence of the depressed lipoprotein lipase and hepatic lipase activities and impaired clearance of lipoproteins. However, there is some evidence that the lipoproteins overproduction might also contribute to hypertriglyceridemia in CRF. This study was performed to test the hypothesis that the increased rate of lipogenesis consequent to upregulation of fatty acid synthase (FAS), a key lipogenic enzyme, gene expression could contribute to overproduction of triacylglycerols and to hypertriglyceridemia in CRF. FAS activity, FAS protein mass (Western blot analysis), and FAS mRNA level (Northern blot analysis) in liver and epididymal white adipose tissue (WAT) were measured in male Wistar rats 6 weeks after subtotal (5 of 6) nephrectomy or sham operation. Moreover, the rate of lipogenesis in WAT was determined. The CRF group showed significant increase in FAS gene expression (measured as activity, mRNA, and protein abundance) in both liver and WAT. This was associated with the increase in the lipogenesis rate and with the increase in plasma triacylglycerol and VLDL concentrations. Our results suggest that not only decreased removal, but also an increase of triacylglycerol production could contribute, in part, to the CRF-associated hyperlipidemia. Upregulation of FAS gene expression, shown in this report for the first time, reveals another factor involved in disturbed lipid metabolism in CRF. It seems that elevated plasma insulin and cytokine concentration could play an important role in the mechanism responsible for the increased FAS gene expression in CRF.
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PMID:Upregulation of fatty acid synthase gene expression in experimental chronic renal failure. 1248 75

Lipid disorders are one of the known metabolic changes associated with chronic renal failure (CRF) [1, 2]. They are present as: hypertriglyceridemia--existed in 60% of CRF patients and hypercholesterolemia observed in 20-30% of people with this syndrome. These disorders, what was shown also in our own studies, are existing in different intensity in patients treated with maintenance haemodialysis [3], peritoneal dialysis [4] and after renal transplantation as well [5]. Mechanism of hypertriglyceridemia, despite over thirty years of studies, is still not finally elucidated. The opinion that it is a result of impaired triglyceride removal (due to decreased activities of both lipoprotein and hepatic lipases) is well documented, however the role of lipogenesis in its development is obscure [6, 7]. The reports concerning this problem contain contradictory data. In our studies performed several years ago we have shown that lipogenesis rate in white adipose tissue of uremic rats is significantly augmented [8, 9, 10] due to activation of free fatty acid synthase. Therefore, recently we paid once again our attention on the activity of this lipogenesis rate limiting enzyme responsible for the long term regulation. We measured its activity, protein abundance and mRNA level in liver and epididymal white adipose tissue of rats with surgically induced renal failure (two-stage subtotal nephrectomy). The results support the thesis that lipogenesis takes a part in a hypertriglyceridemia found in renal failure. There have been observed a significant increase in plasma triglyceride and VLDL concentrations in uremic animals and it was associated with the increase of FAS activity, FAS protein abundance and FAS mRNA. The results were similar in both studied tissues. Moreover, there have been also observed the increased activities of malic enzyme, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. All these enzymes participate in NADPH production, which is a necessary substrate for fatty acid biosynthesis [11, 12, 13]. Concluding, it appears that the rise in plasma triglyceride and VLDL concentrations observed in CRF rats is not only the result of increased liver and white adipose tissue lipogenesis rate. One has to remember, that these date are strictly original and enabling to elucidation further pathogenesis of hyperlipidemia in CRF. In the second set of experiments performed also in rats with experimentally induced CRF we have found that hypercholesterolemia observed in those animals is dependent on the significant activation of cholesterol synthase, induced by increased production of this enzyme (increment of protein abundance and synthase mRNA [14, 15]. Simultaneously, we have performed original studies on the diurnal rhythm of cholesterologenesis, showing that activity of this process is significantly augmented during whole twenty four hours [15]. Summarizing, one have to underline that our observations have important impact to the elucidation of lipid disturbances pathomechanism. Nevertheless further studies are necessary to establish how experimental data are corresponding with human pathology.
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PMID:[Pathomechanism of hyperlipoproteinemia in chronic renal failure]. 1497 58

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