Disease relevance of Lpl

• To better characterize the increase in lipoprotein lipase (LPL) translation by hypothyroidism, adipocytes were prepared from control and hypothyroid rats [1].
• The increased body weight of OVX rat was paralleled by a greater retroperitoneal adipose tissue mass (P <.01), which was in turn associated with a marked rise in LPL activity (P <.005) and a slight decrease in HSL activity (P <.05) compared to intact animals [2].
• These data may suggest a role for LPL in the pathophysiology of diabetic neuropathy [3].
• The striking sensitivity of muscle LPL to inactivity and low-intensity contractile activity may provide one piece of the puzzle for why inactivity is a risk factor for metabolic diseases and why even non-vigorous activity provides marked protection against disorders involving poor lipid metabolism [4].
• These results demonstrate that adipose LPL becomes resistant to insulin in diet-induced IR and further suggest that, under certain nutritional conditions, modifications in adipose LPL modulation associated with insulin resistance, along with low muscle LPL, heightens postprandial hypertriglyceridemia through attenuated triglyceride clearance [5].

Psychiatry related information on Lpl

• The localization of LPL within these structures suggests that the uptake of triglyceride fatty acids is an integral part of normal lipid metabolism of the central nervous system and may be important in regulating feeding behavior and/or maintaining normal neuronal function [6].
• The activities of lipoprotein lipase and of enzymes involved in triacylglycerol synthesis in rat adipose tissue. Effects of starvation, dietary modification and of corticotropin injection [7].
• Heparin-releasable LPL activities, mass and mRNA were measured in heart, diaphragm and soleus muscle and epididymal fat after food deprivation and 1, 2, 4 and 8 h postprandially [8].
• In controlled studies of young rats, it was shown that physical activities associated with walking and standing were especially important for maintaining a high level of lipoprotein lipase (LPL) activity in postural skeletal muscles (slow-twitch oxidative muscles) [9].

High impact information on Lpl

• LPL induction of lipoprotein uptake significantly increased the rates of choline incorporation into phosphatidylcholine (PC) and disaturated PC, and these effects were associated with a three-fold increase in the activity of the rate-regulatory enzyme for PC synthesis, cytidylyltransferase [10].
• Compared with native LPL, a fusion protein of glutathione S-transferase with the catalytically inactive carboxy-terminal domain of LPL did not activate CT despite inducing VLDL uptake [10].
• First, transfection of CHO cells with expression vectors for several syndecan core proteins produced parallel increases in the cell association and degradation of lipoproteins enriched in lipoprotein lipase, a heparan-binding protein [11].
• Administration of NO-1886 increased LPL enzyme mass in postheparin plasma and mRNA activity in epididymal adipose tissue, and it was concluded that the mode of action of this compound is stimulation of tissue LPL synthesis [12].
• Administration of NO-1886 increased LPL activity in the postheparin plasma, adipose tissue, and myocardium of rats, and produced a reduction in plasma triglyceride levels with concomitant elevation of HDL cholesterol levels [12].

Chemical compound and disease context of Lpl

• Clearance of emulsion triolein was affected much less and could be accounted for by residual triolein in remnants, suggesting that triacylglycerol lipolysis by lipoprotein lipase was unaffected by hypothyroidism but that clearance of remnants from plasma was decreased [13].
• We conclude that an HFS diet induces changes in LPL and VLDL-R in a manner which favors shunting of dietary fat from skeletal muscle to adipose tissue and decreases TG-rich lipoprotein clearance contributing to increased plasma lipids and obesity [14].
• Our study indicates that the LPL-promoting agent NO-1886 may be potentially beneficial in the treatment of obesity and obesity-linked health problems in postmenopausal women [15].
• Hyperinsulinemia, changes in body weight, plasma PHLA, and tissue LPL activities did not consistently predict the influence of sex steroid treatment on plasma triglyceride concentrations [16].
• Nitric oxide mediates endotoxin-induced hypertriglyceridemia through its action on skeletal muscle lipoprotein lipase [17].

Biological context of Lpl

• PPAR-gamma activation mediates adipose depot-specific effects on gene expression and lipoprotein lipase activity: mechanisms for modulation of postprandial lipemia and differential adipose accretion [18].
• These data suggest that lipolysis of triacylglycerol-rich chylomicron by LPL is necessary for postprandial vitamin E transport to the liver and subsequent transport to the other tissues [19].
• Significantly greater activities of LPL, HSL, and LPL:HSL in adipose of MF rats suggested a greater capacity for fat accumulation which was not realized at the limited energy intake [20].
• OVX-DHEA rats displayed a reduced adiposity and a lighter RP fat depot, which was associated with a decrease in LPL and an increase in HSL activities, compared to untreated OVX animals [21].
• LPL activity was significantly increased at day 5 and remained elevated until day 14 of gestation [22].

Anatomical context of Lpl

• Fasting alone increased activity in both the capillary-bound LPL and type L hormone-sensitive lipase (HSL) fractions of cardiac muscle [23].
• Adipose tissue and liver LPL activities were not modified by the type of starch in the diet [24].
• Neither alpha-tocopherol administration nor Triton WR1339 injection affected (P >/= 0.05) the alpha-tocopherol concentration in the perirenal adipose tissue, epididymal fat, and soleus muscle despite a high expression of LPL in the adipose tissue and muscle [19].
• These findings therefore show that in spite of reduced uptake of orally administered triglycerides due to decreased LPL activity, maternal alcohol feeding during lactation in the rat preserves the mammary gland triglyceride content thanks to enhanced lipogenetic activity [25].
• OVX-DHEA rats, compared to untreated OVX animals, had a smaller retroperitoneal fat depot, which correlated with a decrease in LPL activity (P <.005) and moderate increase in both HSL activity and beta3-AR density (P <.05) [2].

Associations of Lpl with chemical compounds

• These effects were consistent with increased LPL and HSL activities as well as respiration rates, mainly in response to exogenous palmitate [26].
• RESULTS: Exposure to rosiglitazone for 24 h induced ucp-1, lpl and hsl gene expression and when rosiglitazone was combined with insulin a synergistic effect on lpl and ucp-3 mRNA expression was produced [26].
• Colchicine injection was used as a tool to potentiate the increase in intracellular lipoprotein lipase (type L hormone-sensitive lipase) activity normally seen with fasting to determine if elevation of enzyme activity by this method produced a reduction in endogenous triacylglycerol (TG) in rat heart [23].
• Because a similar mechanism of LPL regulation occurs in response to epinephrine, the absence of the translation repressor may be a mechanism for the loss of sensitivity of hypothyroid cells for catecholamines [1].
• Translational regulation of lipoprotein lipase by thyroid hormone is via a cytoplasmic repressor that interacts with the 3' untranslated region [1].

Enzymatic interactions of Lpl

• Monoglyceride lipase catalyzes the last step in the hydrolysis of stored triglycerides in the adipocyte and presumably also complements the action of lipoprotein lipase in degrading triglycerides from chylomicrons and very low density lipoproteins [27].

Regulatory relationships of Lpl

• Neither insulin- nor glucose-dependent insulinotropic polypeptide-stimulated lipoprotein lipase was modified by the presence of the antibiotic actinomycin-D in the incubation medium, indicating that these two hormones exert their actions on the pre-existing cellular pool of lipoprotein lipase [28].
• At d 28 of protein malnutrition, plasma total lipolytic activities were significantly reduced in both depleted groups, (P < 0.05); hepatic lipase values represented 23% of the control value and lipoprotein lipase activity was about 11% of the control value [29].
• Acute leptin administration induced hypertriglyceridaemia (31% increase in plasma triacylglycerols) which was not associated with changes in lipoprotein lipase activity in white adipose tissue [30].

Other interactions of Lpl

• These depot-specific effects may be mediated by differential regulation of key metabolic genes, including LPL, 11beta-HSD-1, and UCP-1 [18].
• These data show that alpha-tocopherol transfer activity of LPL in adipose tissue and muscle is not important for alpha-tocopherol transport to the tissue after alpha-tocopherol intake or that the amount transferred is small relative to the tissue concentration [19].
• Isoproterenol inhibited expression of LPL and FAS mRNAs in cells from the younger but not older rats [31].
• Apolipoprotein E and lipoprotein lipase increase triglyceride-rich particle binding but decrease particle penetration in arterial wall [32].
• The high-lard diet greatly decreased FAS, HMG-CoA reductase, and LPL activities; it also reduced H-TGL activity [33].

Analytical, diagnostic and therapeutic context of Lpl

• Lipoprotein lipase (LPL) [EC 3.1.1.34] activity in adipose tissue was higher in the capsaicin and capsinoid-II groups than in the control group [34].
• In adipose lumbar tissue of late pregnant rats, LPL activity decreased to about one-third that of the virgin control animals, with < 10% of initial LPL mRNA expressed as determined by Northern blots [35].
• The sequential inhibitory effect of TGF-beta2 on C/EBPalpha, C/EBPbeta, and PPARgamma2 resulted in reduced LPL expression and abolition of bone marrow stromal cell adipogenic differentiation, which contributed to prevent bone loss induced by skeletal unloading [36].
• Fasting augmented the activity of both AMPK and luminal LPL on immediate removal of hearts, effects that still remained even after in vitro perfusion of hearts for 1 h [37].
• Hearts from overnight-fasted rats were first perfused with heparin to release LPL, and homogenates from these hearts were then used to measure total and phospho-AMPK-alpha by Western blotting [37].

References