Action of some effectors on the hydrolysis of long-chain triglycerides by pancreatic lipase

Benzonana, Gilbert; Desnuelle, P.

doi:10.1016/0005-2760(68)90069-6

Cited by 153 publications

(30 citation statements)

References 14 publications

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“…This parallel pattern of ␤-hydroxybutyrate plasma concentration and PL activity supports the proposed role of ketones in mediating the dietary regulation of PL and may explain the more robust response of PL to low amounts of MCT. In contrast, lipolysis of emulsified LCT may be inhibited by the soaps formed during the reaction and by their poor diffusion to the aqueous phase (39), which might result in less stimulation of the proposed mediators at lower dietary levels.…”

Section: Discussionmentioning

confidence: 99%

Regulation of Pancreatic Lipase by Dietary Medium Chain Triglycerides in the Weanling Rat

Birk

Brannon

2004

Pediatr Res

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Pancreatic lipase (PL) and its related protein 1 (PLRP1) are regulated by the amount of dietary fat through an apparent transcriptional mechanism. Regulation of PL and PLRP1 by type of fat (chain length and degree of saturation) is less well understood. The aim of this study was to determine whether mediumchain triglycerides regulate PL and PLRP1. For 7 d, weanling (21-d-old) Sprague Dawley male rats were fed diets low (11% of energy), moderate (40% of energy), or high (67% of energy) in trioctanoate/tridecanoate (MCT) or safflower (low fat only) oils. Food consumption decreased as dietary MCT increased, and the consumption of MCT diets was lower than that of the lowsafflower (control) diet. Final body weight was similar among rats fed the low-or moderate-MCT or control diets, but was significantly reduced (17%) in those fed the high-MCT diets. PL activity was significantly elevated 53-60% (p Ͻ 0.002) in rats fed low and moderate MCT diets, respectively, compared with that of rats fed high-MCT or control diets. PL and PLRP1 mRNA levels were not significantly different among diets, suggesting that chain length regulates PL and PLRP1 translationally or posttranslationally. The ␤-hydroxybutyrate plasma concentration was significantly (p Ͻ 0.02) higher (85%) in rats consuming low-MCT diet compared with those of rats fed the control diet. MCT at low levels, but not high levels, increase PL activity without changing its mRNA levels. Pancreatic lipase (PL) is the main enzyme responsible for digestion of dietary triglycerides. PL catalyzes the hydrolysis of 56% of the fatty acids of dietary triglycerides, and gastric lipase, an additional 10% (1). PL and its related protein PLRP1, a homologous protein of unknown function (2), are secreted by the pancreas and regulated by dietary fat (3-5). Considerable amount of work has been reported about the dietary regulation of PL by triglycerides, but many of the studies before 1994 used a cDNA probe initially believed to be PL and subsequently shown to be PLRP1 (2). PL was initially cloned by Lowe and co-workers (6) and referred to as rat PL3 by Wicker-Planquart and Puigserver (7). PL demonstrates the classical dependence on colipase for its lipolytic activity. PLRP1 (known before 1994 as pancreatic lipase 1/2) is highly homologous to PL (65%) (2, 8), but to date no known lipolytic activity of PLRP1 has been reported. Site-directed mutagenesis of two amino acids in PLRP1 to those seen in PL restores full colipase-dependent lipolytic activity of PLRP1, suggesting that PLRP1 may be a nonfunctional homologue of PL (9). Another homologue, pancreatic lipase related protein 2 (PLRP2) has 65% identity to PL and hydrolyzes triglycerides, phospholipids, and galactolipids. PLRP2 has low colipase dependence and does not exhibit bile salt inhibition as PL does (2,8,10,11). It is unknown whether PLRP2 is regulated by dietary fat.The pancreas normally produces and secretes 3-to 10-fold excess lipase; therefore, the physiologic importance of regulating PL has been questioned. However, the dieta...

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Section: Discussionmentioning

confidence: 99%

Regulation of Pancreatic Lipase by Dietary Medium Chain Triglycerides in the Weanling Rat

Birk

Brannon

2004

Pediatr Res

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“…They, therefore, represent major advances over titrimetric assays using long-chain triglycerides, which suffer from poor linearity of product formation and insensitivity due to incomplete titration of fatty acids (24). All 15 steatorrheic patients had measurable amounts of colipase and lipase in every collection period and all showed some response to secretin-pancreozymin.…”

Section: Discussionmentioning

confidence: 99%

Colipase and maximally activated pancreatic lipase in normal subjects and patients with steatorrhea.

Gaskin¹,

Durie²,

Hill³

et al. 1982

J. Clin. Invest.

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“…Each kinetic assay was performed in a thermostated (37 Њ C) vessel in a final assay volume of 10 ml containing 0.25 ml of substrate emulsion and 9.75 ml of 0.25 mM Tris-HCl buffer, 150 mM NaCl, and 2 mM CaCl 2 . Lipolysis of long-chain TAGs or cholesteryl esters is inhibited by the free fatty acids (or their soaps) released, and this inhibition can be prevented by adding CaCl 2 and NaCl to the reaction medium (30). When required, BSA (0.6 M final concentration), ␤ -CD (3 mM final concentration), or NaTDC (4 mM final concentration) was added to the assay medium.…”

Section: Lipolytic Activity Measurementsmentioning

confidence: 99%

Continuous monitoring of cholesterol oleate hydrolysis by hormone-sensitive lipase and other cholesterol esterases

Ali

Carrière

Verger

et al. 2005

Journal of Lipid Research

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Hormone-sensitive lipase (HSL) contributes importantly to the hydrolysis of cholesteryl ester in steroidogenic tissues, releasing the cholesterol required for adrenal steroidogenesis. HSL has broad substrate specificity, because it hydrolyzes triacylglycerols (TAGs), diacylglycerols, monoacylglycerols, and cholesteryl esters. In this study, we developed a specific cholesterol esterase assay using cholesterol oleate (CO) dispersed in phosphatidylcholine and gum arabic by sonication. To continuously monitor the hydrolysis of CO by HSL, we used the pH-stat technique. For the sake of comparison, the hydrolysis of CO dispersion was also tested using other cholesteryl ester-hydrolyzing enzymes. The specific activities measured on CO were found to be 18, 100, 27, and 3 mol/min/mg for HSL, cholesterol esterase from Pseudomonas species, Candida rugosa lipase-3, and cholesterol esterase from bovine pancreas, respectively. The activity of HSL on CO is ‫ف‬ 4-to 5-fold higher than on long-chain TAGs. In contrast, with all other enzymes tested, the rates of TAG hydrolysis were higher than those of CO hydrolysis. The relatively higher turnover of HSL on CO observed in vitro adds further molecular insight on the physiological importance of HSL in cholesteryl ester catabolism in vivo. Thus, HSL could be considered more as a cholesteryl ester hydrolase than as a TAG lipase. FFAs are an important source of energy in mammals. Hormone-sensitive lipase (HSL) is thought to play a crucial role in the mobilization of FFAs from the triacylglycerols (TAGs) stored in adipocytes (for review, see 1). In vivo, HSL is activated by phosphorylation via cAMP-dependent kinase in response to various lipolytic hormones, such as catecholamines. Phosphorylation of HSL leads to its translocation from the cytoplasm to the lipid droplet (2). Insulin acts as an antilipolytic hormone by phosphorylating and activating phosphodiesterase 3B, which hydrolyzes cAMP and thus reduces the hydrolysis of TAG (1) by HSL. In addition to adipocytes, HSL is expressed in other tissues (3), including skeletal muscle, heart, brain, pancreatic ␤ cells, adrenal gland, ovaries, testes, and macrophages (1).HSL also plays an important role in the mobilization of cholesterol from cholesteryl ester. Cholesteryl esters provide the cholesterol required for steroid synthesis in steroidogenic tissues, such as the adrenal cortex. The level of cholesteryl ester hydrolase activity in the adrenals of HSLnull mice has been found to be reduced by more than 98% compared with that in wild-type mice, which suggests that HSL is mainly responsible for the hydrolysis of most of the cholesteryl esters present in this tissue and that it is involved in the intracellular processing of the cholesterol required for adrenal steroidogenesis (4, 5). Furthermore, evidence has been presented in various studies (6, 7) that HSL contributes importantly to the hydrolysis of most of the cholesteryl esters present in macrophage foam cells. However, Contreras (8) has reported that cholesteryl esters from...

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Action of some effectors on the hydrolysis of long-chain triglycerides by pancreatic lipase

Cited by 153 publications

References 14 publications

Regulation of Pancreatic Lipase by Dietary Medium Chain Triglycerides in the Weanling Rat

Regulation of Pancreatic Lipase by Dietary Medium Chain Triglycerides in the Weanling Rat

Colipase and maximally activated pancreatic lipase in normal subjects and patients with steatorrhea.

Continuous monitoring of cholesterol oleate hydrolysis by hormone-sensitive lipase and other cholesterol esterases

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