Lipoprotein lipase activity in neonatal-rat liver cell types

Burgaya, Ferràn; Peinado, J.; Vilaró, Senén; Llobera, Miquel; Ramı́rez, Ignasi

doi:10.1042/bj2590159

Cited by 44 publications

(29 citation statements)

References 52 publications

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“…In liver, LPL synthesis has been reported to be confined to Kupffer cells (48), although there is evidence that in newborn rats LPL is expressed in hepatocytes (49). Although it is possible that part of the LXR␣ selectivity for LPL expression is attributable to differential cell type expression of the two LXR genes, we note that the in vitro data on Lpl promoter binding and activation by the LXRs (Figs.…”

Section: Discussionmentioning

confidence: 61%

Regulation of Lipoprotein Lipase by the Oxysterol Receptors, LXRα and LXRβ

Zhang

Repa²,

Gauthier³

et al. 2001

Journal of Biological Chemistry

254

190

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Lipoprotein lipase (LPL) is a key enzyme for lipoprotein metabolism and is responsible for hydrolysis of triglycerides in circulating lipoproteins, releasing free fatty acids to peripheral tissues. In liver, LPL is also believed to promote uptake of high density lipoprotein (HDL)-cholesterol and thereby facilitate reverse cholesterol transport. In this study we show that the Lpl gene is a direct target of the oxysterol liver X receptor, LXR␣. Mice fed diets containing high cholesterol or an LXRselective agonist exhibited a significant increase in LPL expression in the liver and macrophages, but not in other tissues (e.g. adipose and muscle). Studies in Lxrdeficient mice confirmed that this response was dependent more on the presence of LXR␣ than LXR␤. Analysis of the Lpl gene revealed the presence of a functional DR4 LXR response element in the intronic region between exons 1 and 2. This response element directly binds rexinoid receptor (RXR)/LXR heterodimers and is sufficient for rexinoid-and LXR agonist-induced transcription of the Lpl gene. Together, these studies further distinguish the roles of LXR␣ and ␤ and support a growing body of evidence that LXRs function as key regulators of lipid metabolism and are anti-atherogenic.

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Section: Discussionmentioning

confidence: 61%

Regulation of Lipoprotein Lipase by the Oxysterol Receptors, LXRα and LXRβ

Zhang

Repa²,

Gauthier³

et al. 2001

Journal of Biological Chemistry

254

190

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“…27 All measurements of lipoprotein lipase activity in plasma and liver homogenates were carried out in the presence of anti-rat hepatic lipase antiserum. 28 The homogenate and plasma protein content were determined with the Bradford method.…”

Section: Activity Of Lipasesmentioning

confidence: 99%

Effect of oral oleoyl-estrone treatment on plasma lipoproteins and tissue lipase activities of Zucker lean and obese female rats

et al. 2002

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OBJECTIVE:To study the effect of oral oleoyl-estrone on the plasma lipoprotein profile and tissue lipase activities in order to determine the handling of circulating lipids by adipose tissue, liver and muscle of obese female rats. DESIGN: Lean (Fa=?) and obese (fa=fa) female Zucker rats treated for 10 days with a daily gavage of 0.2 ml sunflower oil containing 0 (controls) or 10 mmol=kg of oleoyl-estrone. After sacrifice, samples of tissues and plasma were taken. MEASUREMENTS: Plasma lipoprotein classes and composition; lipoprotein lipase and hepatic lipase activities in plasma, liver, skeletal muscle and periovaric and mesenteric white adipose tissue (WAT). RESULTS: Oleoyl-estrone decreased plasma cholesterol (mainly in HDLs: 76%) of lean rats, but dramatically decreased all lipid classes in obese rats, in which chylomicra and VLDL lost most of their triacylglycerols (95 and 81%, respectively). Hepatic lipase activity decreased markedly with oleoyl-estrone in all groups, both in plasma (79% lean, 100% obese) and liver (62% in both groups). Lipoprotein lipase activity was largely unchanged by oleoyl-estrone in lean rats, but in the obese it decreased in WAT (82% in periovaric, and 49% in mesenteric), and increased in plasma (Â4) and in skeletal muscle (Â5); liver levels showed no change. CONCLUSIONS: The shift observed in obese rats from a decrease in liver and WAT lipoprotein lipase and hepatic lipase activities to an increase in muscle lipoprotein lipase is coincident with the hypolipemic effect of oleoyl-estrone, especially in obese rats, and indicates that muscle is a key site for the disposal of endogenous fat mobilized due to oleoyl-estrone treatment.

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“…First, it could be synthesized locally, either by hepatic parenchymal cells (49)(50)(51) or by macrophages (52, 53) within the liver. The second possibility, for which more evidence exists in the adult mammal, is that LpL is transported from its major sites of synthesis in extrahepatic tissues to the liver.…”

Section: Discussionmentioning

confidence: 99%

Lipoprotein lipase modulates net secretory output of apolipoprotein B in vitro. A possible pathophysiologic explanation for familial combined hyperlipidemia.

Williams¹,

Petrie²,

Brocia³

et al. 1991

J. Clin. Invest.

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We showed previously that net secretory output of apolipoprotein B (apo B) from cultured human hepatoma cells (HepG2) is regulated by rapid reuptake of nascent lipoproteins before they have diffused away from the vicinity of the cells. We now sought to determine if the nascent lipoproteins could be remodeled to enhance or impede reuptake. We found that lipoprotein lipase (LpL), an enzyme that hydrolyzes lipoprotein triglyceride, reduced HepG2 output of apo B to one-quarter to one-half of control. The reduction was apparent during co-incubations as short as 2 h and as long as 24 h. Heparin, which blocks receptor-mediated binding of lipoproteins, abolished the effect of LpL on apo B output, without causing enzyme inhibition. To assess uptake directly, we prepared labeled nascent lipoproteins. LpL tripled the cellular uptake of labeled nascent lipoproteins, from 15.2%±0.7% to 48.

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Lipoprotein lipase activity in neonatal-rat liver cell types

Cited by 44 publications

References 52 publications

Regulation of Lipoprotein Lipase by the Oxysterol Receptors, LXRα and LXRβ

Regulation of Lipoprotein Lipase by the Oxysterol Receptors, LXRα and LXRβ

Effect of oral oleoyl-estrone treatment on plasma lipoproteins and tissue lipase activities of Zucker lean and obese female rats

Lipoprotein lipase modulates net secretory output of apolipoprotein B in vitro. A possible pathophysiologic explanation for familial combined hyperlipidemia.

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