Antibodies to lipoprotein lipase application to perfused heart

Schotz, Michael C.; Twu, Jer-Shung; Pedersen, M. Elizabeth; Chen, Chi-Hong; Garfinkel, Arlene S.; Borensztajn, Jayme

doi:10.1016/0005-2760(77)90140-0

Cited by 42 publications

(4 citation statements)

References 17 publications

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“…Immunotitration experiments Antibodies to purified rat heart LPL were isolated as described by Schotz et al (1977). Control IgG and the anti-LPL IgG fractions were dialysed before use against 5 mM-sodium phosphate/15 mM-NaCl, pH 7.5, and then centrifuged to remove any insoluble material.…”

Section: Triacylglycerol Hydrolase Assaysmentioning

confidence: 99%

“…LPL (EC 3.1.1.34) has been located at the capillary endothelium of the heart by immunocytochemical techniques (Pedersen et al, 1983). Displacement of this endothelium-bound enzyme by perfusion with heparin (Borensztajn & Robinson, 1970) or inhibition of enzyme activity by antibodies to LPL (Schotz et al, 1977) results in a marked decrease in the ability of the heart to metabolize chylomicrons. Therefore LPL at the capillary endothelium of the heart has a functional role in the degradation of the TG component of circulating lipoproteins.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of triacylglycerol hydrolase activities in isolated myocardial cells from rat heart

Ramı́rez¹,

Kryski²,

Ben-Zeev³

et al. 1985

Biochemical Journal

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Triacylglycerol (TG) hydrolase activities were characterized in myocytes isolated from rat hearts. Acid hydrolase activity with a pH optimum of 5 could be measured in myocyte homogenates, and the subcellular distribution suggested that this activity originated in lysosomes. Lipoprotein lipase (LPL) was also present in myocyte homogenates, as evidenced by TG hydrolase activity that was stimulated by serum and apolipoprotein CII, and inhibited by apolipoprotein CIII2, high ionic strength (NaCl and MgCl2, I = 1 M) and antibodies to LPL. Serum-independent neutral (pH 7.5) TG hydrolase activity was less sensitive to inhibition by 1 M-NaCl, by antibodies to LPL and by preincubation at 40 degrees C than was serum-stimulated hydrolase activity. Furthermore, there were modest but significant differences in the subcellular distribution of the serum-independent and serum-stimulated hydrolase activities. Hydrolase activities in myocyte homogenates could be solubilized by 7.2 mM-deoxycholate. Acid hydrolase activity was recovered in the unbound fraction after heparin-Sepharose chromatography, whereas LPL was bound to the affinity column and was eluted by 0.9-1.2 M-NaCl. Approximately one-third of the serum-independent TG hydrolase activity was not bound to the heparin-Sepharose affinity column. This unbound TG hydrolase activity had a pH optimum of 7 and was stimulated by 50 mM-MgCl2, but not by serum and was resistant to inhibition by high ionic strength (1 M-NaCl), to preincubation at 40 degrees C for 2 h, and by antibodies to LPL. It is concluded that, in addition to an acid lysosomal TG hydrolase and LPL, myocytes from rat heart contain a serum-independent TG hydrolase with unique characteristics.

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Section: Triacylglycerol Hydrolase Assaysmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of triacylglycerol hydrolase activities in isolated myocardial cells from rat heart

Ramı́rez¹,

Kryski²,

Ben-Zeev³

et al. 1985

Biochemical Journal

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“…The endothelium-bound enzyme (Fig. 1) is often referred to as " functional LPL" since displacement of the enzyme by perfusion with heparin [4,15] or inhibition of enzyme activity by antibodies to LPL [16] resulted in marked reduction in the ability of perfused hearts, for example, to degrade lipoproteins.…”

Section: Introductionmentioning

confidence: 99%

Regulation of the synthesis, processing and translocation of lipoprotein lipase

Braun

Severson

1992

Biochemical Journal

288

194

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“…Since heparin does not rapidly penetrate the vascular endothelium, they suggested that the heparin-releasable LPL represented the enzyme at the endothelium. This has been designated as the "functional LPL", since it is this fraction that can act on lipoproteins in blood (45). It was concluded that modulation of LPL in heart entailed a shift of the enzyme to or from the endothelium, in contrast to adipose tissue, where regulation was exerted on the amount of the enzyme (28).…”

mentioning

confidence: 98%

A transcription-dependent mechanism, akin to that in adipose tissue, modulates lipoprotein lipase activity in rat heart

Wu¹,

Zhang²,

Gupta³

et al. 2007

American Journal of Physiology-Endocrinology and Metabolism

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The enzyme lipoprotein lipase (LPL) releases fatty acids from lipoprotein triglycerides for use in cell metabolism. LPL activity is rapidly modulated in a tissue-specific manner. Recent studies have shown that in rat adipose tissue this occurs by a shift of extracellular LPL toward an inactive form catalyzed by an LPL-controlling protein whose expression changes in response to the nutritional state. To explore whether a similar mechanism operates in other tissues we injected actinomycin D to block transcription of the putative LPL controlling protein(s). When actinomycin was given to fed rats, heparin-releasable LPL activity increased by 160% in heart and by 150% in a skeletal muscle (soleus) in 6 h. Postheparin LPL activity in blood increased by about 200%. To assess the state of extracellular LPL we subjected the spontaneously released LPL in heart perfusates to chromatography on heparin-agarose, which separates the active and inactive forms of the lipase. The amount of lipase protein released remained relatively constant on changes in the nutritional state and/or blockade of transcription, but the distribution between the active and inactive forms changed. Less of the LPL protein was in the active form in perfusates from hearts from fed compared with fasted rats. When glucose was given to fasted rats the proportion of LPL protein in the active form decreased. Actinomycin D increased the proportion that was active, in accord with the hypothesis that the message for a rapidly turning over LPL-controlling protein was being removed.

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Antibodies to lipoprotein lipase application to perfused heart

Cited by 42 publications

References 17 publications

Characterization of triacylglycerol hydrolase activities in isolated myocardial cells from rat heart

Characterization of triacylglycerol hydrolase activities in isolated myocardial cells from rat heart

Regulation of the synthesis, processing and translocation of lipoprotein lipase

A transcription-dependent mechanism, akin to that in adipose tissue, modulates lipoprotein lipase activity in rat heart

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