Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.1.34 (lipoprotein lipase)
7,025 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Post-heparin lipoprotein lipase (PH-LPL)-high density lipoprotein cholesterol (HDL-C) interrrelationships were assessed in 9 subjects with documented familial hyperalphalipoproteinemia (FHA) and in 8 controls to focus on potential biochemical etiologies of FHA and relationships of HDL-C to triglyceride hydrolysis and PH-LPL. FHA subjects had mean HDL-C and HDL2-C levels > twice controls; their PH-LPL levels (mean +/- SEM) (3.14 +/- 2.3 mumol FFA/h/ml) were also > twice that of controls (15.0 +/- 1.6) (P < 0.01), but post-heparin hepatic lipase levels (PH-HL) in the FHA and control subjects did not differ (18.1 +/- 1.6 vs 26.6 +/- 4.3, P > 0.1). For all subjects (FHA and controls) PH-LPL was positively correlated with HDL-C (r = 0.79, P < 0.01) and with HDL2-C (r = 0.90, P < 0.01), but not with HDL3-C (r = --0.02). There were no significant PH-HL and HDL-C interrelationships, P > 0.1. The amount of apo CII (the primary activator of PH-LPL) in HDL2 was greater in the FHA (mean +/- SEM) (16.1 +/- 2.5 microgram/ml plasma) than in control subjects (4.7 +/- 0.9, P < 0.01). There were strong positive correlations between HDL2 apo CII and both PH-LPL (r = 0.79, P < 0.01) and HDL2-C (r = 0.80, P < 0.01). Apo CII as a percentage of HDL2 protein was higher in FHA than control subjects (mean +/- SEM) (1.2 +/- 0.3% vs 0.5 +/- 0.2%, P < 0.01). Apo CII as a percentage of HDL3 protein was similar in FHA and control subjects. We postulate that increased turnover rate of triglyceride-rich lipoproteins due to high LPL activity may be an important factor leading to the elevation of HDL-C in FHA. The highly significant positive correlation between HDL2-C and PH-LPL provides strong clinical evidence for the theory that HDL2 is formed during the hydrolysis of triglycceride-rich lipoproteins. The high concentration of HDL2 apo CII in FHA subjects may be caused by increased catabolism of triglyceride-rich lipoproteins in the presence of high endothelial LPL, with transfer of apo CII from very low to high density lipoproteins.
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PMID:Post-heparin plasma lipoprotein and hepatic lipases. Relationships to high density lipoprotein cholesterol and to apolipoprotein CII in familial hyperalphalipoproteinemic and in normal subjects. 742 98

Adipose tissue lipoprotein lipase (ATLPL) is responsible for the provision of lipoprotein-derived fatty acids to adipocytes for storage as triglycerides. Fasting ATLPL has been shown to be decreased in non-insulin-dependent diabetes mellitus (NIDDM), an insulin-resistant state. Medically uncomplicated obesity, another state of relative insulin resistance, is associated with decreased stimulation of the enzyme in response to metabolic stimuli. It was therefore hypothesized that the increased insulin resistance of NIDDM would result in an even greater defect in the response of ATLPL to insulin/glucose. Gluteal adipose tissue biopsies were performed in 13 premenopausal obese women with NIDDM, before and after 6 hours of intravenous insulin and glucose. Metabolic data from these studies were then compared with those obtained from 26 nondiabetic obese women of similar age, weight, and fasting insulin concentration (obese controls [OBC]). As expected, fasting gluteal ATLPL activity was lower in the NIDDM group than in OBC (3.7 +/- 0.9 v 11.1 +/- 1.6 nmol free fatty acids [FFA]/min/10(6) cells, P = .0003). The change in ATLPL activity (delta ATLPL) in response to a 6-hour insulin/glucose infusion was not statistically different between the two groups (2.2 +/- 1.1 v 4.7 +/- 1.2, P = .114). However, in NIDDM subjects there was a strong positive relationship between delta ATLPL and glycohemoglobin (GHb) level (r = .883, P = .0001).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Glycohemoglobin levels relate to the response of adipose tissue lipoprotein lipase to insulin/glucose in obese non-insulin-dependent diabetes mellitus. 747 37

In extrahepatic tissues lipoprotein lipase (LPL) hydrolyzes triglycerides thereby generating FFA for tissue uptake and metabolism. To study the effects of increased FFA uptake in muscle tissue, transgenic mouse lines were generated with a human LPL minigene driven by the promoter of the muscle creatine kinase gene. In these mice human LPL was expressed in skeletal muscle and cardiac muscle, but not in other tissues. In proportion to the level of LPL overexpression, decreased plasma triglyceride levels, elevated FFA uptake by muscle tissue, weight loss, and premature death were observed in three independent transgenic mouse lines. The animals developed a severe myopathy characterized by muscle fiber degeneration, fiber atrophy, glycogen storage, and extensive proliferation of mitochondria and peroxisomes. This degree of proliferation suggests that FFA play an important role in the biogenesis of these organelles. Our experiments indicate that LPL is rate limiting for the supply of muscle tissue with triglyceride-derived FFA. Improper regulation of muscle LPL can lead to major pathological changes and may be important in the pathogenesis of some human myopathies. Muscle-specific LPL transgenic mouse lines will serve as a useful animal model for the investigation of myopathies and the biogenesis of mitochondria and peroxisomes.
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PMID:Muscle-specific overexpression of lipoprotein lipase causes a severe myopathy characterized by proliferation of mitochondria and peroxisomes in transgenic mice. 763 90

Obesity is an increasingly prevalent problem, and long-term maintenance of the weight-reduced state is difficult for the obese individual. Following weight reduction, many metabolic changes occur. Among these is an increase in adipose tissue lipoprotein lipase (ATLPL), which predicts an alteration in lipid fuel partitioning which may then contribute to resumption of the obese state. The purpose of this study was to test whether changes in skeletal muscle LPL (SMLPL) and its response to insulin/glucose after sustained weight reduction also indicate a potential altered partitioning of lipid fuels away from oxidative pathways in muscle to storage in adipose tissue. Biopsies of vastus lateralis muscle were carried out in premenopausal obese women (n = 11, 94 +/- 4 kg, mean +/- SEM) before and after consumption of a 900 kcal day-1 diet for 3 months followed by 3 months of isocaloric maintenance of the reduced weight (n = 11, 82 +/- 4 kg). SMLPL activity was measured in the fasted state and after 6 h insulin/glucose infusion, before and after sustained weight loss. SMLPL activities were also measured in six normal weight women. Fasting SMLPL activity in obese women (3.9 +/- 0.3 nmol FFA min-1 g-1) was similar to that measured in normal weight control women (4.4 +/- 0.5). Unlike normal weight controls in whom a 6 h insulin/glucose infusion decreased SMLPL activity, in obese women the response of SMLPL was positive (normal weight vs. obese: delta -0.8 +/- 0.3 vs. delta 1.6 +/- 0.5, P = 0.002). Following maintained weight reduction, fasting SMLPL in the obese group was reduced to 1.2 +/- 0.3 (obese before weight loss vs. obese after: P = 0.0001). This change in fasting SMLPL activity following weight loss/maintenance correlated with the resultant change in percent body fat (r s = 0.663, P = 0.026).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sustained weight reduction in moderately obese women results in decreased activity of skeletal muscle lipoprotein lipase. 765 17

Lipid profile and postheparin lipolytic activity (PHLA) were investigated in 21 patients with acute renal failure (ARF), 24 with chronic renal failure (CRF), and 23 healthy volunteers. Plasma triglycerides were significantly elevated in ARF (155.19 +/- 72.39 mg/dL) as well as CRF (166.79 +/- 72.36 mg/dL), as compared to controls (89.91 +/- 23.41 mg/dL, p < .001). PHLA was determined at 5, 10, 30, and 60 min after intravenous heparin (100 U/kg) and was observed to be reduced in ARF (7.82 +/- 1.41 mumol FFA/mL/h) as well as CRF (8.44 +/- 1.68 mumol FFA/mL/h) at 10 min, as compared to the values in the control subjects (12.03 +/- 2.43 mumol FFA/mL/h, p < .01). No correlation was found between PHLA and plasma triglycerides in ARF or CRF. In 15 patients in each group, PHLA subfractions, hepatic triglyceride lipase (HTGL), and lipoprotein lipase (LPL) were determined at similar time intervals after heparin. Both fractions were found to be reduced significantly (p < .01) in ARF as well as in CRF versus controls. These findings indicate that the lipid alterations in acute and chronic renal failure share common features including hypertriglyceridemia and reduced PHLA and its subfractions HTGL and LPL.
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PMID:Postheparin lipolytic activity in acute and chronic renal failure. 785 16

Plasma lipoprotein and apoprotein (apo) A-I, A-II and B concentrations and post-heparin plasma lipoprotein lipase (LPL) activity and mass were measured in 13 children with congenital nephrotic syndrome of the Finnish type (CNF) six months after renal transplantation to determine whether the severe lipid abnormalities documented prior to and during peritoneal dialysis would normalize. Plasma total triglyceride decreased by 52% (p < 0.001), VLDL triglyceride by 55% (p < 0.01) and total cholesterol by 17% (p < 0.01). HDL cholesterol increased by 51% (p < 0.001), whereas no significant change was observed in LDL cholesterol. Despite these improvements, plasma lipoprotein concentrations were still abnormal after transplantation. Total (p < 0.01) and VLDL triglyceride (p < 0.05) as well as total (p < 0.01), VLDL (p < 0.01) and LDL cholesterol (p < 0.01) were higher than in control children. HDL cholesterol normalized. Plasma apo A-I and A-II concentrations were normal, but the apo B concentration remained high (p < 0.01). Post-heparin LPL activity and mass were normal (25.0 +/- 9.1 mumol FFA/ml/h and 227.2 +/- 88.4 ng/ml). The mean cyclosporine dose correlated positively with the serum creatinine concentration (r = +0.72, p < 0.01). Positive correlations were also observed between total (r = +0.68, p < 0.05) and VLDL triglyceride (r = +0.62, p < 0.05) and the serum creatinine concentrations. We conclude that renal transplantation substantially improves the triglyceride and cholesterol abnormalities in CNF but significant abnormalities still persist.
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PMID:Short-term effects of renal transplantation on plasma lipids and lipoprotein lipase in children with congenital nephrosis. 805 Feb 8

Heparin is a well-known, widely used anticoagulant drug. In addition to its anticoagulant properties, however, it also has a marked influence on fat metabolism. Postprandial lipoproteins may contribute significantly to the development of coronary heart disease. Therefore, it is important to evaluate the effects of heparin on these lipoproteins. The effect of continuous heparin administration on postprandial lipoprotein metabolism was studied in 11 patients with thromboembolic disease. Results were compared with those in a group of six patients given no heparin. Two vitamin A-fat loading tests were done: the first, 5 days before heparin was started and the second, on the fourth day of continuous heparin drip of 1000 U/h, maintaining PTT levels at twice the baseline. To study the effect of acute heparin, an additional fat loading test was done in five patients on the first day of heparin treatment. Vitamin A, specifically labels intestinally derived lipoproteins with retinyl palmitate (RP). The concentrations of chylomicron (Sf > 1000)- and nonchylomicron (Sf < 100)-retinyl palmitate were measured for 10 h postprandially. Four days of continuous intravenous heparin administration increased the area below the chylomicron RP curve from 11091 +/- 4393 to 17684 +/- 5949 micrograms/l.h (P < 0.003). When measured on the first day of heparin treatment in five patients, the area of the chylomicron fraction was reduced from 16678 +/- 6895 to 10474 +/- 3893 micrograms/l.h (P < 0.05). Postheparin lipoprotein lipase activity was significantly lower on the fourth day of heparin, administration than before treatment: 1.8 +/- 1.1 vs. 4.1 +/- 1.3 mumol/FFA per ml per h, respectively (P < 0.0005). In the six control patients with thromboembolic disease in whom heparin therapy was not indicated, no changes in postprandial lipoprotein levels or in lipolytic activity during hospitalization were found. The study demonstrates that 4 days of heparin administration causes an accumulation of chylomicrons in the circulation, most probably as a result of a marked decrease in serum lipolytic activity.
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PMID:Continuous intravenous heparin administration in humans causes a decrease in serum lipolytic activity and accumulation of chylomicrons in circulation. 816 26

Glucocorticoid receptor (GR) status was studied in adipose tissue from omental and sc abdominal adipose tissue. As the effects of glucocorticoids may be due to alteration of triglyceride uptake in adipose tissue, the activity of the enzyme lipoprotein lipase (LPL) was also investigated. Fat biopsies were obtained from 8 women and 11 men matched for age and body mass index. Omental adipose tissue contained 4 times the number of GR as sc abdominal adipose tissue (42.0 +/- 4.1 vs. 10.5 +/- 2.3 fmol/mg protein, respectively; P < 0.001) with similar Kd values. No gender difference in GR number was observed in adipose tissue from the two regions. LPL activity in omental adipose tissue was about 820 nmol FFA/h.g wet wt in both sexes, whereas LPL activity in sc adipose tissue was about 2- to 4-fold lower. Moreover, LPL activity in sc adipose showed marked gender differences, with 2-fold higher activity in women than in men (474 +/- 84 vs. 238 +/- 35 nmol FFA/h.g wet weight; P < 0.03). Finally, there was no correlation between GR number and LPL activity when each fat depot was investigated separately. However, a positive correlation between LPL activity and glucocorticoid binding was found when the data from both regions were pooled (r = 0.55; P < 0.01). In conclusion, human adipose tissue dexamethasone binding was higher in omental than in sc adipose tissue, without any gender difference. LPL activity was also higher in omental than in sc adipose tissue in both groups, without any gender difference. On the other hand, sc LPL activity was higher in females than in men. A correlation (positive) between GR number and LPL activity was only found when the data from both regions were pooled.
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PMID:Characterization of regional and gender differences in glucocorticoid receptors and lipoprotein lipase activity in human adipose tissue. 820 Sep 37

To clarify the role of defective lipoprotein lipase (LPL) in hypertriglyceridemia, the LPL masses and LPL activities in post-heparin plasma (PHP) were studied in severe hypertriglyceridemias. The developed sandwich enzyme immunoassay for the LPL was sensitive from 0.5 to 20 ng/ml of LPL in human PHP. The plasma LPL mass increased by heparin injection (30 USP units/kg) and was found to positively correlate with LPL activity. The mean LPL activity from PHP of normal controls was 2,960 +/- 1,057 nmol/ml/h. The mean LPL masses from human pre- and 15-min post-heparin plasma from normal subjects were 25 +/- 5 ng/ml and 224 +/- 60 ng/ml, respectively. Thus the specific activity of LPL from PHP of normal controls was calculated to be 13.3 mumol FFA released/h/microgram LPL. Among hypertriglyceridemic patients with over 1,000 mg/dl of serum triglyceride, the incidence of patients with LPL masses less than -2 standard deviations (S.D.) of those of average normal control subjects was found to be 27%. Seventy percent of patients showed specific activities within + 2 S.D. of those of average control LPL, and 30% showed significantly low specific activities less than -2 S.D. despite the fact that LPL masses were not less than -2 S.D. of the average normal controls. These results suggest that the evaluation of LPL masses in PHP would be useful for finding functionally defective LPL in patients with hypertriglyceridemia, and that up to 30% severe hypertriglyceridemias may have functionally defective LPL.
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PMID:Lipoprotein lipase mass and activity in severe hypertriglyceridemia. 822 62

Obesity is a risk factor of atherosclerosis. The TG content of a fat cell is determined by the balance of lipogenesis from plasma FFA and glucose and lipolysis by hormone-sensitive lipase (HSL). Plasma FFA is produced by TG lipolysis by lipoprotein lipase (LPL). Insulin stimulates LPL activity and inhibits HSL activity. Therefore, hyperinsulinemia stimulates TG accumulation in fat cells. Insulin also stimulates fat cell proliferation. Hyperinsulinemia is a major factor for obesity. Portal FFA stimulates VLDL synthesis and gluconeogenesis and inhibits insulin degradation in the liver. Therefore, visceral obesity is important as a risk factor of atherosclerosis. However the increase of total adipose tissue mass is more important for blood pressure and cardiac performance.
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PMID:[Atherosclerotic and hemodynamic effects of obesity]. 841 92


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