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)

Methods to quantitate factors in milk relevant to cold-induced lipolysis are described. Skim milk was incubated with milk fat globules isolated from a pool of normal milk and a fixed amount of purified lipoprotein lipase. The release of fatty acids in 24 h at 4 degrees C was determined. Most skim milk samples inhibited lipolysis, but the effect varied greatly. Skim milk from milk prone to spontaneous lipolysis was less inhibitory than skim milk from normal milk. In general, both the casein and the serum fractions of skim milk inhibited lipolysis. However, variation was greater in the effects of individual samples of milk serum. In a few extreme cases, with samples from milk with spontaneous lipolysis, the serum fraction actually stimulated lipolysis. Globules were isolated and then incubated with skim milk from normal milk and a fixed amount of purified lipoprotein lipase. This gave a measure of accessibility to lipolysis of milk fat globules in normal skim milk. There was a considerable variation in propensity toward lipolysis between milk fat globules from individual milk samples. Milk showing different levels of lipolysis obtained from five cows revealed that skim milk inhibition of lipolysis and the propensity of milk fat globules toward lipolysis were characteristic for each cow.
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PMID:Methods to assess the propensity of milk fat globules toward lipolysis and the ability of skim milk to inhibit lipolysis. 368 Jul 23

Hydrolysis of a long-chain triglyceride substrate by purified cow milk lipoprotein lipase, in the absence of blood serum, was changed by adding heated skim milks. Preincubation of the substrate with small amounts of several skim milks increased (+50 to 300%) lipoprotein lipase activity. By contrast, greater amounts of skim milk increased further or decreased lipoprotein lipase activity (+ 300 to -90%). The inhibitory effect was due to substrate surface protection. Results obtained after removal of casein (by isoelectric precipitation or by ultracentrifugation) and of whey proteins (by heat treatment) showed that the effect of skim milk was due to the proteose-peptone fraction. Fractionation of the proteose-peptone fraction into component 5-enriched fraction and component 3-enriched fractions suggested that the activating effect was due partially to proteose-peptone component 5, and the inhibitory effect resulted from component 3. These effects were overcome by blood serum.
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PMID:Effects of different skim milk fractions on activity of cow milk purified lipoprotein lipase. 372 38

The distribution of lipoprotein lipase among cream, casein, and milk serum can be evaluated by addition of a trace amount of 125I-labeled lipoprotein lipase to milk. Radioactive lipase was distributed in parallel to endogenous lipase under several conditions. In some milk samples, binding of lipase to cream increased when the milk was cooled. Correlation was good between bound labeled lipase and degree of cold-induced lipolysis in corresponding milk samples. Binding of lipase to cream or to casein was not saturable by addition of two-to threefold more lipase than is normally present in milk. In milk with a relatively high fraction of lipase bound to cream, a correspondingly lower fraction was associated with casein, whereas the fraction of lipase in milk serum was similar in all milk samples. Cold-induced binding of lipoprotein lipase to cream was not fully reversed when the milk was warmed again. Heparin released lipase from casein and increased the amount of lipase bound to cream after cooling.
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PMID:Iodine-125-labeled lipoprotein lipase as a tool to detect and study spontaneous lipolysis in bovine milk. 374 79

Ten-week-old female obese and lean Zucker rats were given access to three separate macronutrient sources (casein, starch, and lard) for 7 days. They were then either adrenalectomized (ADX) or given a sham operation. Rats were assigned to one of three groups and given a daily injection of either 0, 2, or 10 mg of corticosterone. They continued to select a diet for another 17 days, after which they were killed, and their blood was assayed for corticosterone, adrenocorticotropin hormone (ACTH), insulin, glucose, and triglyceride. Retroperitoneal and parametrial fat depots were excised and sampled for lipoprotein lipase activity, fat cell size, and number. Body composition was also determined. Selection patterns of lean and obese rats were markedly affected by both ADX and corticosterone replacement. All three groups of sham-operated obese rats ate significantly more fat than did sham-operated lean rats. Adrenalectomy significantly reduced fat intakes in both obese and lean rats. Corticosterone therapy restored fat appetites of lean and obese rats in a dose-dependent fashion. In comparison to ADX lean rats, ADX obese rats reduced their normally elevated levels of blood glucose, plasma triglycerides, and insulin to within normal limits. Similarly, adipose cellularity of the ADX obese rats was reduced to that of sham-operated lean rats. Carcass fat was significantly reduced after adrenalectomy. Corticosterone therapy prevented the reduction in a dose-dependent way.
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PMID:Some metabolic and behavioral effects of adrenalectomy on obese Zucker rats. 377 20

Raw, bovine bulk tank milk and milks from selected cows were separated by ultracentrifugation into four major fractions: casein, sloughed membrane material, serum, and milk fat globule membrane. Milk lipoprotein lipase activity was measured by the pH stat method and protein determinations were made by the Lowry procedure for each of the four fractions in order to calculate specific activity (units per milligram of protein). In six farm-cooled bulk milk samples stored less than or equal to 24 h, casein had a significantly higher milk lipoprotein lipase total activity, 35.66 units/ml of milk, than all of the fractions. Serum had the next highest activity with 11.69 units/ml of milk. Fluff and milk fat globule membrane had activities of .80 and .41 units/ml of milk, respectively. The specific activity of the fluff was 3.3 milk lipoprotein lipase units/mg of protein, which was significantly higher than the casein and serum fractions in pooled milk. Milks from five cows in midlactation were assayed individually for milk lipoprotein lipase activity and protein content immediately after milking and after 12, 24, 48 and 72 h of cold (4 degrees C) storage. Fresh warm milk was characterized by the absence of fluff. Casein had the highest mean activity (29.91 units/ml), followed by serum (10.25 units/ml) and milk fat globule membrane (.26 units/ml) in the warm milk from the individual cows. Upon cooling to 4 degrees C, significant increases in enzyme activity in the fluff and milk fat globule membrane fractions were observed at 12 h.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Milk lipoprotein lipase distribution in the major fractions of bovine milk. 384 45

Synthesis of fatty acids was measured in the liver and in epididymal adipose tissue of sand rats and albino rats. In chow-fed sand rats the rate of hepatic lipogenesis, as measured by the incorporation of 3H2O into fatty acids, was four- to sevenfold higher than in albino rats and in sand rats on a low-calorie saltbush diet. The contribution of [14C]glucose to lipogenesis in sand rat liver was lower than in albino rats. In fed sand rats lipogenesis incorporating 3H2O was stimulated by casein but not by glucose. In adipose tissue, lipogenesis measured 1 h after administration of 3H2O was much lower in sand rats than in albino rats. In vitro incorporation of [14C]glucose or acetate into adipose tissue fatty acids was negligible. In adipose tissue, uptake of very-low-density lipoproteins (VLDL) and lipoprotein lipase activity were sevenfold higher than in albino rats. Activities of NADP-malate dehydrogenase, acetyl CoA carboxylase, and fatty acid synthetase were considerably higher in the liver of chow-fed sand rats than in albino rats. It was concluded that obesity in sand rats originates from hepatic lipogenesis without a significant contribution of local fatty acid synthesis in adipose tissue.
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PMID:Lipogenesis in the sand rat (Psammomys obesus). 634 15

The influence of mastitis and early lactation, and the effect of treating milk with heparin, blood serum and trypsin, on the proportion of lipoprotein lipase (LPL) activity in mild serum was investigated. The relative importance of milk serum LPL and LPL bound to micellar casein in promoting lipolysis was also examined. Colostrum contained LPL activity, 45% of which was found in the serum phase in samples obtained from the first milking post partum, but this value fell to 34% in samples taken 24 h later. The proportion of serum LPL was also increased in milks from quarters infected with Staphylococcus aureus, but not after overnight treatment of normal milk at 4 degrees C with 5% (w/v) blood serum or 2 microgram/ml trypsin. The addition of 5 microgram/ml heparin resulted in a consistent increase in serum LPL which varied between 14 and 50% of total milk LPL. Heparin did not release all the enzyme bound to casein micelles even after a second heparin treatment of resuspended micelles. Serum LPL was more effective in promoting lipolysis and was more responsive to blood serum activation than LPL bound to casein micelles. Lipolysis increased after heparin treatment but the increase was not related to serum LPL activity.
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PMID:Factors affecting the distribution of lipoprotein lipase activity between serum and casein micelles in bovine milk. 707 45

Vervet monkeys (Cercopithecus aethiops pygerethrus) were fed cholesterol-free, semipurified diets containing 40% sucrose, 25% casein, 15% cellulose and 14% peanut oil (PNO), randomized peanut oil (RPNO) or corn oil (CO). After 4 months, serum cholesterol and triglyceride levels, serum lecithin-cholesterol acyl transferase (LCAT) activity and plasma lipoprotein lipase (LPL) activity were similar in all groups. Livers of monkeys fed CO converted 156% more acetate and 24% more mevalonate to cholesterol than those of monkeys fed RPNO. Cholesterogenesis in RPNO-fed monkeys was enhanced compared to PNO (68% from acetate; 62% from mevalonate). Incidence of atherosclerosis was 33% in monkeys fed RPNO, 80% in those fed CO and 90% in those fed PNO. Extent of sudanophilia was lowest in aortas of monkeys fed RPNO. Incidence of arteriosclerosis was 40% in monkeys fed CO, 56% in those fed RPNO and 70% in those fed PNO. Extent of aortic surface showing arteriosclerosis was highest in monkeys fed RPNO.
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PMID:Influence of native and randomized peanut oil on lipid metabolism and aortic sudanophilia in the vervet monkey. 708 18

Feeding of a glycerine rich diet with sufficient supply of essential amino acids (mixture of casein and gelatine) causes a significant reduction of the serum triglyceride level in rats. To study some aspects of this triglyceride lowering effect the in vivo incorporation of C14-1-acetate and C14-1-palmitate into the serum and liver lipids as well as the lipoprotein lipase and the hormone sensitive lipolytic activity of the epididymal adipose tissue in vitro were estimated. After feeding the gelatine containing diet the incorporation of labelled acetate and palmitate into the serum triglycerides was significantly decreased with no change of the incorporation into the liver triglycerides and without detectable accumulation of liver lipids. The decreased serum triglyceride level of the serum corresponded to a decreased lipoprotein lipase activity in the epididymal adipose tissue, whereas the basal and norepinephrine stimulated lipolysis of this tissue was not affected. From these results it is concluded that due to feeding of a glycine rich diet the triglyceride secretion of the liver is decreased leading to a lower serum triglyceride level.
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PMID:The hypolipaemic action of a glycine rich diet in rats. 742 87

The following studies have been carried out to compare the effects of fish protein with other dietary proteins on plasma cholesterol and lipoproteins in animal models and in humans. In rabbits, fish protein has been shown to induce relatively variable effects compared to casein and soy protein on serum cholesterol depending in part on the origin of dietary lipids with which it is combined. In a protein-lipid interaction study, casein, soy or cod protein were combined with corn or coconut oil. Casein and soy protein in the presence of corn oil induced lower serum cholesterol levels despite its combination with either corn or coconut oil. This is in part due to serum high density lipoprotein (HDL) cholesterol concentrations, which were consistently higher with cod protein than with either casein or soy protein, regardless of the dietary lipid source. In rabbits, this rise in HDL cholesterol was associated with a decrease in very low density lipoprotein (VLDL) triglycerides and an increase in postheparin plasma lipoprotein lipase activity. The effects of lean white fish on plasma lipoproteins also have been investigated in post and premenopausal women fed a low-fat, high P/S (polyunsaturated/saturated fat) ratio diet. In postmenopausal women, lean white fish compared with other animal protein products induced higher concentrations of plasma cholesterol, LDL-apolipoprotein (apo) B and HDL cholesterol, mainly in the HDL3 fraction. In premenopausal women, lean white fish induced lower concentrations of VLDL triglycerides and higher concentrations of LDL-apoB in plasma.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of dietary fish protein in the regulation of plasma lipids. 758 95


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