Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.34 (lipoprotein lipase)
 7,025 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The stroma-vascular fraction (SVF) of inguinal and epididymal fat pads of 4 week-old rats was studied by electron microscopy. Among the various cell types, endothelial cells and preadipocytes were found in both SVF, while mesothelial cells were only detected in the epididymal SVF. The resulting heterogeneity of primary culture and the adipoconversion of the fat cell precursors were studied in a serum-supplemented medium enriched with insulin (14.5 nM) and exogenous triglycerides. Despite the heterogeneity of the inoculum, the primary cultures were rather homogeneous, fat cell precursors being the main cell type. Distinctive contaminant fibroblast-like cells were observed in both cultures, whereas epithelial-like cells, which correspond most probably to mesothelial cells, were only found in epididymal cultures. Differentiation of fat cell precursors was assessed by the appearance of lipoprotein lipase (LPL) and glycerol-3-phosphate dehydrogenase (GPDH). LPL activity was found in the same level in cells of both deposits while GPDH activity was elevated in inguinal vs epididymal derived stroma-vascular cells. The different adipose conversion pattern of both cultures was confirmed by morphological quantification: the maturation of epididymal fat cell precursors was faster but less extensive. These differences could be related mainly to regional localization rather than to different maturation of the two fat deposits.
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PMID:The stroma-vascular fraction of rat inguinal and epididymal adipose tissue and the adipoconversion of fat cell precursors in primary culture. 209 4

This study was designed to evaluate the effect of guar gum on the postprandial increase in plasma lipids, insulin and lipoprotein lipase (LPL) activity in white adipose tissue (WAT). Male rats were given ad libitum access to purified diets containing either no fiber or 5% guar gum for 3 wk. The animals were killed at various times after a meal (10% of daily ad libitum intake of their respective diets). Consumption of guar gum resulted in smaller final body weight (-7%, P less than 0.05) and ad libitum food intake (-10%, P less than 0.05). The difference in epididymal WAT weight induced by the concomitant diet was relatively larger (-29%, P less than 0.05) than that of whole body weight. Although no difference was seen in fasting plasma total and high density lipoprotein cholesterol levels between dietary groups, the postprandial increase in these variables was larger in the animals given the fiber-free meal than in those receiving the fiber-supplemented meal (P less than 0.01). Guar also attenuated the postprandial rise in plasma triacylglycerols. The presence of fiber in the meal reduced the postprandial increase in plasma insulin (P less than 0.01). The meal-induced rise in LPL activity of WAT was significantly smaller (P less than 0.02) in the animals fed the diet containing fiber than in those receiving the fiber-free diet. Thus, guar gum altered the activity of LPL in WAT, an effect that may be related to the insulin response to this dietary component.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Attenuation of the meal-induced increase in plasma lipids and adipose tissue lipoprotein lipase by guar gum in rats. 215 72

This study was conducted to determine serum lipid levels and the activity of lipoprotein lipase in epididymal white adipose tissue of rats undergoing exercise training. During the 8-week period of treatment, one group of rats was kept sedentary and the remaining animals were exercise trained either continually (1 h of daily treadmill running) or intermittently (alternate weeks of daily running and inactivity). Exercise training, either continual or intermittent, decreased postprandial serum total and high-density lipoprotein cholesterol concentrations, which returned to sedentary levels in the intermittently trained animals following a week of rest. Lipoprotein lipase activity in whole epididymal adipose pad was lower in rats trained continually than in the sedentary group at the end of the treatment. The intermittent training program elicited large fluctuations in both the specific (per milligram of protein) and total (per tissue) activity of lipoprotein lipase in white adipose tissue. During rest periods, enzyme activity rose to levels that were higher than those of sedentary rats, whereas lipase activity was below that of sedentary animals following a week of running. In the last exercise--rest cycle, body weight gain of the intermittently trained rats was nearly abolished during the week of running, but it increased above that of sedentary animals during weeks of rest. The present results suggest that the modulation of lipoprotein lipase activity in white adipose tissue is one of the adaptations that take place to accommodate the fluctuations in the rate of energy deposition that occur in the rat during an intermittent training program.
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PMID:Lipoprotein lipase activity in white adipose tissue of rats subjected to exercise--rest cycles. 217 44

Tumour necrosis factor (TNF) has previously been shown to decrease lipoprotein lipase (LPL) activity and mRNA levels in 3T3-L1 cells and in adipose tissue from rats and guinea pigs when injected in vivo, but not to alter LPL activity in human adipocytes incubated in vitro. The effect of recombinant human TNF on LPL activity and mRNA levels in rat epididymal adipose tissue incubated in vitro was examined. LPL activity and mRNA levels fell in adipose tissue taken from fed rats and incubated in Krebs-Henseleit bicarbonate medium with glucose. The addition of insulin and dexamethasone prevented these falls. TNF (400 ng/ml) produced a fall of approx. 50% in LPL activity after 2 h of incubation and of approx. 30% in LPL mRNA levels after 3 h. TNF did not decrease LPL activity in isolated adipocytes. These results demonstrate that rat adipose tissue incubated in vitro is responsive to TNF whereas isolated adipocytes are not.
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PMID:Regulation of lipoprotein lipase activity and mRNA content in rat epididymal adipose tissue in vitro by recombinant tumour necrosis factor. 219 21

The purpose of this study was to compare lipoprotein lipase (LPL) and hepatic lipase (HL) releasing activities of different low molecular weight heparins (LMWH) and of a standard heparin. In vivo, the injection of most LMWH led to a LPL and HL releasing activity inferior to that obtained with a standard heparin. The releasing of LPL by muscle in vitro and of HL by perfused liver was identical with both types of heparins, but in epididymal adipose tissue, LPL activity released by LMWH was generally higher than the activity released by unfractionated heparin. We have no explanation for this apparent contradiction between the in vivo and in vitro results.
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PMID:In vivo and in vitro release of lipoprotein lipase and hepatic lipase by low molecular weight heparins. 254 47

Siberian hamsters exhibit decreased body weight and fat after initial exposure to short photoperiods and increased body weight and fat after extended short photoperiod exposure. The purpose of the present experiments was to determine if uniform changes in white adipose tissue (WAT) pad weights and lipid metabolism correspond to these short photoperiod-induced changes in body fat. Carcass lipid content and testes and fat pad weights [retroperitoneal WAT (RWAT), epididymal WAT (EWAT), and inguinal and dorsal subcutaneous WAT, respectively] were decreased in male hamsters relative to their long day counterparts after 6 and 12 wk of short-day exposure. Moreover, EWAT and RWAT weight, EWAT specific lipoprotein lipase activity, and specific and total lipogenesis were disproportionately decreased relative to the subcutaneous fat pads. The changes in fat pad weight and metabolism were generally reversed coincident with the return to a long-day-like reproductive status after prolonged short-day exposure (24 and 30 wk). In a less detailed experiment, female Siberian hamsters had decreased body, fat pad, and uterine weights after 6 wk of short-day exposure; however, no fat pad-specific changes in weight were observed. The results of these experiments demonstrate that short-day-exposed male Siberian hamsters may be a useful model for examining mechanisms underlying fat pad-specific responses. In addition, gender appears to influence the pattern of short-day-induced lipid depletion in this species.
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PMID:Regional differences in fat pad responses to short days in Siberian hamsters. 260 8

Adipose tissue blood flow was measured in five depots, and plasma concentrations of glucose, insulin, and triglyceride were measured at 0, 15, 30, and 45 min after the start of a meal in unanesthetized, freely moving rats. In addition, adipose tissue lipoprotein lipase activity was measured in four depots before and 45 min after the start of a meal. Plasma glucose was significantly elevated only at the 15-min time point, and while plasma triglyceride increased these changes did not reach significance. Plasma insulin was significantly elevated at all time points after a meal. Feeding resulted in a consistent decrease of adipose tissue blood flow expressed per gram wet weight of tissue. This decrease was maximal at 30 min after the start of feeding. The decrease in adipose tissue blood flow averaged 45% at 45 min after the start of feeding for the five depots evaluated. Lipoprotein lipase activity significantly increased in the retroperitoneal and mesenteric fat depots at 45 min after the meal start, but did not change in the epididymal or dorsal subcutaneous fat depots. These results suggest that a decrease in adipose tissue blood flow is a normal result of a meal in the rat. The regional specificity of changes in adipose tissue lipoprotein lipase activity supports the concept of regional specificity of function for adipose tissue and suggests that the mesenteric and retroperitoneal depots are particularly important for the storage of triglycerides immediately after a meal.
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PMID:Regional changes in adipose tissue blood flow and metabolism in rats after a meal. 267 49

The effects of several levels of chronic energy restriction on epididymal and perirenal adipose tissue cellularity and lipoprotein lipase activity, serum glucose and insulin and hepatic enzyme activities were studied in lean Fa/- and genetically obese fafa rats. The restricted rats were compared to rats fed ad libitum 24/24h or 8/24h. Restricting time of feeding was associated with increases in fat cell number in the lean, increases in perirenal adipose tissue fat cell size and serum insulin in the obese and increases in lipoprotein lipase activity in both phenotypes. Mild food restriction (-25%) had similar effects in the obese: perirenal adipose tissue fat cell size and serum insulin levels were even higher but fat cell hyperplasia was reduced. Restriction by 50% normalized lipoprotein lipase activity and markedly reduced fat cell size in the lean; in the obese, lipoprotein lipase activity and insulin levels were similar to or lower than those of the corresponding ad libitum 24/24h group but fat cell hypertrophy was not particularly affected. Restriction by 75% in the obese prevented adipocyte hyperplasia. Furthermore, lipoprotein lipase activity in adipose tissue was normalized, serum insulin and lipids being within normal limits. However, these animals had large adipocytes and were still fat.
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PMID:Different levels of food restriction have opposite effects on adipocyte cellularity and lipoprotein-lipase activity in obese rats. 269 8

Groups of 4-week old, male Osborne-Mendel rats were given high fat diet (HFD) for 12 weeks; one group was fed control diet (CON) for 28 weeks. HFD rats were transferred to control diet (HFDCON) and diets restricted to 80% (HFDR80) or 60% (HFDR60) of HFDCON intake for another 16 weeks, while one group continued on HFD. Body, liver and epididymal adipose tissue (EPI) weight, and the EPI/body weight ratio of HFDR60 group decreased significantly. EPI lipid content and total lipoprotein lipase activity also declined in response to 40% restriction. Overall, the data indicate that 40% energy restriction can stabilize body weight at a reduced level, and mobilize adipose lipid to meet the energy needs of HFD rats.
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PMID:Adaptive response of rats with diet-induced adiposity to energy restriction. 274 30

When added to murine adipocytes in culture, tumor necrosis factor (TNF) decreases the levels of lipoprotein lipase (LPL). Semb et al (1987. J. Biol Chem. 262: 8390-8394) have shown that administration of murine TNF to rats decreases lipoprotein lipase (LPL) in the epididymal fat pad with maximal inhibition requiring several hours. We have now tested the effects of treatment of rats with TNF on LPL activity in a variety of tissues and find that few show decreases in LPL under conditions that acutely increase serum triglycerides. Ninety minutes after treatment of male rats with human TNF (25 micrograms/200 g, i.v.), serum triglycerides rose 2.2-fold but there was no decrease in LPL activity in epididymal fat. Sixteen hours after TNF treatment LPL activity had decreased by 44% in epididymal fat, consistent with the previously reported data. In contrast, in female rats, no significant decrease was seen in LPL activity in parametrial adipose tissue at either 90 min or 16 hr after TNF administration despite increases in serum triglycerides (1.8-fold and 1.5-fold, respectively). There was little change in LPL activity in most other adipose tissue sites of male or female rats at either time after TNF treatment. No effect of TNF was seen on heart or diaphragm muscle LPL at any time. TNF treatment of both male and female rats produces consistent increases in de novo hepatic lipogenesis in vivo under conditions that increase serum triglycerides. It is unlikely that the limited effects of TNF on LPL in vivo can account for the rapid and sustained increase in serum triglycerides.
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PMID:Effect of tumor necrosis factor administration in vivo on lipoprotein lipase activity in various tissues of the rat. 275 38


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