1
|
Schackmann MJ, Ofman R, Dijkstra IM, Wanders RJ, Kemp S. Enzymatic characterization of ELOVL1, a key enzyme in very long-chain fatty acid synthesis. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:231-7. [DOI: 10.1016/j.bbalip.2014.12.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 12/05/2014] [Indexed: 10/24/2022]
|
2
|
Engelen M, Schackmann MJA, Ofman R, Sanders RJ, Dijkstra IME, Houten SM, Fourcade S, Pujol A, Poll-The BT, Wanders RJA, Kemp S. Bezafibrate lowers very long-chain fatty acids in X-linked adrenoleukodystrophy fibroblasts by inhibiting fatty acid elongation. J Inherit Metab Dis 2012; 35:1137-45. [PMID: 22447153 PMCID: PMC3470694 DOI: 10.1007/s10545-012-9471-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 02/14/2012] [Accepted: 02/22/2012] [Indexed: 12/31/2022]
Abstract
X-linked adrenoleukodystrophy (X-ALD) is caused by mutations in the ABCD1 gene encoding ALDP, an ATP-binding-cassette (ABC) transporter located in the peroxisomal membrane. ALDP deficiency results in impaired peroxisomal β-oxidation and the subsequent accumulation of very long-chain fatty acids (VLCFA; > C22:0) in plasma and tissues. VLCFA are primarily derived from endogenous synthesis by ELOVL1. Therefore inhibiting this enzyme might constitute a feasible therapeutic approach. In this paper we demonstrate that bezafibrate, a PPAR pan agonist used for the treatment of patients with hyperlipidaemia reduces VLCFA levels in X-ALD fibroblasts. Surprisingly, the VLCFA-lowering effect was independent of PPAR activation and not caused by the increase in either mitochondrial or peroxisomal fatty acid β-oxidation capacity. In fact, our results show that bezafibrate reduces VLCFA synthesis by decreasing the synthesis of C26:0 through a direct inhibition of fatty acid elongation activity. Taken together, our data indicate bezafibrate as a potential pharmacotherapeutic treatment for X-ALD. A clinical trial is currently ongoing to evaluate the effect in patients with X-ALD.
Collapse
Affiliation(s)
- Marc Engelen
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Neurology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Pediatric Neurology/ Emma Children’s Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Martin J. A. Schackmann
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Rob Ofman
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Robert-Jan Sanders
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Inge M. E. Dijkstra
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Sander M. Houten
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Stéphane Fourcade
- Neurometabolic Diseases Laboratory, The Bellvitge Institute of Biomedical Research (IDIBELL), Center for Biomedical Research on Rare Diseases (CIBERER), Barcelona, Spain
| | - Aurora Pujol
- Neurometabolic Diseases Laboratory, The Bellvitge Institute of Biomedical Research (IDIBELL), Center for Biomedical Research on Rare Diseases (CIBERER), Barcelona, Spain
- ICREA (Institució Catalana de Recerca i Estudis Avançats), Barcelona, Spain
| | - Bwee Tien Poll-The
- Department of Neurology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Pediatric Neurology/ Emma Children’s Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Ronald J. A. Wanders
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Stephan Kemp
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Pediatric Neurology/ Emma Children’s Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Clinical Chemistry and Pediatric Neurology, Laboratory Genetic Metabolic Diseases, Academic Medical Center, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands
| |
Collapse
|
3
|
Curran I, Hierlihy SL, Liston V, Pantazopoulos P, Nunnikhoven A, Tittlemier S, Barker M, Trick K, Bondy G. Altered fatty acid homeostasis and related toxicologic sequelae in rats exposed to dietary potassium perfluorooctanesulfonate (PFOS). JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2008; 71:1526-1541. [PMID: 18923995 DOI: 10.1080/15287390802361763] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Perfluorooctanesulfonate (PFOS) is one of a class of industrial chemicals known as perfluoroalkyl acids, which have a wide variety of uses as surfactants and stain repellants. The presence of fluorochemical residues in human blood, plasma, or serum from sample populations worldwide is indicative of widespread human exposure. Previous studies demonstrated that PFOS alters fatty acid metabolism in the liver of rodents and that this leads to peroxisome proliferation. This study was undertaken to (1) confirm the effects of PFOS on rat liver, (2) identify additional target organs and systems, and (3) further explore the biochemical and molecular changes associated with PFOS exposure. The results confirmed that liver was a primary target for PFOS. Hepatomegaly, decreased serum triglycerides and cholesterol, and increased expression of the genes for acyl-coenzymeA oxidase 1 (ACOX1) and cytochrome P-450 4A22 (CYP4A22) were indicative of exposure to a peroxisome proliferator. Changes in liver fatty acid profiles included increased total monounsaturated fatty acid levels and decreased total polyunsaturated fatty acids, as well as an increase in linoleic acid levels and a decrease in longer chain fatty acids. These changes were similar to those induced by relatively weak peroxisome proliferators. Disruptions in hepatic fatty acid metabolism may contribute to changes in red blood cell membranes, resulting in increased lysis and cell fragility. Serum thyroid hormone levels were decreased in PFOS-treated rats, while the kidney and cardiovascular systems were not significant targets. Residue analyses indicated that PFOS accumulation in tissues was dose dependent, appearing preferentially in the liver at lower doses but increasing in serum and other organs relative to liver at higher doses.
Collapse
Affiliation(s)
- Ivan Curran
- Toxicology Research Division, Bureau of Chemical Safety, Food Directorate, Health Canada, Ottawa, Ontario
| | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Kudo N, Toyama T, Mitsumoto A, Kawashima Y. Regulation by carbohydrate and clofibric acid of palmitoyl-CoA chain elongation in the liver of rats. Lipids 2003; 38:531-7. [PMID: 12880109 DOI: 10.1007/s11745-003-1338-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Regulation of palmitoyl-CoA chain elongation (PCE) and its contribution to oleic acid formation were investigated in rat liver in comparison with stearoyl-CoA desaturase (SCD). Hepatic PCE activity was induced by the administration of 20% wt/vol glucose or fructose in the drinking water of normal rats. In streptozotocin-induced diabetic rats, the activities of both PCE and SCD were suppressed, and fructose, but not glucose, feeding caused an increase in the activities of both enzymes. Treatment of normal rats with clofibric acid in combination with carbohydrate further increased PCE, but not SCD, activity. FA analysis of hepatic lipids revealed that the proportion of oleic acid (18:1 n-9) increased upon administration of carbohydrate or clofibric acid. The treatment of rats with clofibric acid in combination with carbohydrate greatly increased the proportion of 18:1 n-9. A significant correlation was observed between PCE activity and the hepatic proportion of 18:1 n-9 (r2 = 0.874, P < 0.01), whereas the relationship between SCD activity and the proportion of 18:1 n-9 was not significant (r2 = 0.552, P > 0.05). Taken together, these results suggest that carbohydrate induces PCE as well as SCD activity to increase the hepatic 18:1 content in rat liver, and the increased PCE activity seems to be responsible for the further increase in 18:1 n-9 when carbohydrate is administered in combination with clofibric acid.
Collapse
Affiliation(s)
- Naomi Kudo
- Faculty of Pharmaceutical Sciences, Josai University, Saitama 350-0295, Japan.
| | | | | | | |
Collapse
|
5
|
Rodríguez C, Cabrero A, Roglans N, Adzet T, Sánchez RM, Vázquez M, Ciudad CJ, Laguna JC. Differential induction of stearoyl-CoA desaturase and acyl-CoA oxidase genes by fibrates in HepG2 cells. Biochem Pharmacol 2001; 61:357-64. [PMID: 11172741 DOI: 10.1016/s0006-2952(00)00557-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
We studied whether two typical effects of fibrates, induction of stearoyl-CoA desaturase (EC 1.14.99.5) and peroxisome proliferation, are related. The effect of bezafibrate on the activity and mRNA of stearoyl-CoA desaturase and acyl-CoA oxidase in the liver and epididymal white adipose tissue of male Sprague-Dawley rats was determined. The same parameters were measured in HepG2 cells, a cell line resistant to peroxisome proliferation, following incubation with ciprofibrate. Bezafibrate increased the hepatic mRNA levels (14.5-fold on day 7) and activity (9.3-fold on day 15) of acyl-CoA oxidase. Stearoyl-CoA desaturase mRNA levels were transiently increased (2.7-fold on day 7), while its activity remained increased at the end of the treatment (2.4-fold). In white adipose tissue, bezafibrate increased the mRNA (5-fold) and activity (1.9-fold) of acyl-CoA oxidase, while stearoyl-CoA desaturase was not modified. Ciprofibrate addition to HepG2 cells cultured in 7% fetal bovine serum (FBS) only increased the stearoyl-CoA desaturase mRNA (1.9-fold). When cells were cultured in 0.5% FBS, ciprofibrate increased acyl-CoA oxidase mRNA (2.2-fold), while the increase in stearoyl-CoA desaturase mRNA was identical (1.9-fold). Further, its activity was also increased (1.5-fold). Incubation of HepG2 cells in the presence of cycloheximide did not alter the capacity of ciprofibrate to induce stearoyl-CoA desaturase mRNA, whereas the presence of actinomycin abolished the induction. In addition, preincubation of HepG2 cells with ciprofibrate increased the rate of stearoyl-CoA desaturase mRNA degradation. The results presented in this study suggest that fibrates induce stearoyl-CoA desaturase activity and mRNA levels independently of peroxisome proliferation.
Collapse
Affiliation(s)
- C Rodríguez
- Unidad de Farmacología y Farmacognosia, Facultad de Farmacia, Universidad de Barcelona, 08028, Barcelona, Spain
| | | | | | | | | | | | | | | |
Collapse
|
6
|
Yoshinari M, Asano T, Kaori S, Shi AH, Wakisaka M, Iwase M, Fujishima M. Effect of gemfibrozil on serum levels of prostacyclin and precursor fatty acids in hyperlipidemic patients with Type 2 diabetes. Diabetes Res Clin Pract 1998; 42:149-54. [PMID: 9925344 DOI: 10.1016/s0168-8227(98)00107-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Lipid-lowering fibrate drugs are known to affect the synthesis of fatty acids, which may alter the prostacyclin synthesis in diabetic patients. Therefore, the serum levels of precursor fatty acids and 6-keto-prostaglandin F1alpha (6-keto PGF1alpha) were determined in ten hyperlipidemic patients with Type 2 diabetes before and after administration of gemfibrozil (900 mg/day) for 3 months, in comparison with the results in seven non-diabetic hyperlipidemic patients. Gemfibrozil significantly reduced the serum concentration of dihomo-7-linolenic acid, total cholesterol and triglycerides, but did not affect the serum levels of arachidonic acid and 6-keto PGF1alpha in diabetic and non-diabetic patients. Thus, gemfibrozil did not affect the synthesis of prostacyclin in spite of the reduction of precursor fatty acids in diabetic and non-diabetic patients.
Collapse
Affiliation(s)
- M Yoshinari
- Second Department of Internal Medicine, Faculty of Medicine, Kyushu University, Maidashi, Fukuoka, Japan.
| | | | | | | | | | | | | |
Collapse
|
7
|
Tetradecylthioacetic acid incorporated into very low density lipoprotein: changes in the fatty acid composition and reduced plasma lipids in cholesterol-fed hamsters. J Lipid Res 1995. [DOI: 10.1016/s0022-2275(20)41089-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
8
|
Vázquez M, Alegret M, López M, Rodríguez C, Adzet T, Merlos M, Laguna JC. Different effects of fibrates on the microsomal fatty acid chain elongation and the acyl composition of phospholipids in guinea-pigs. Br J Pharmacol 1995; 116:3337-43. [PMID: 8719816 PMCID: PMC1909193 DOI: 10.1111/j.1476-5381.1995.tb15144.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
1. The effects in vitro and in vivo of three fibric acid derivatives, clofibrate (CFB), bezafibrate (BFB) and gemfibrozil (GFB) on some enzyme activities related to fatty acid biosynthesis, namely palmitoyl-CoA synthetase and hydrolases (microsomal and cytosolic), NADH and NADPH cytochrome c reductases and acyl-CoA elongases were investigated in guinea-pigs. 2. The three fibrates inhibited acyl-CoA elongation in vitro, irrespective of the substrate of elongation used (saturated, monounsaturated, polyunsaturated) and with an order of potency GFB > BFB > CFB. In the case of GFB, inhibition occurred at concentrations that can be reached in vivo. 3. Microsomal palmitoyl-CoA hydrolase and synthetase were also inhibited in vitro (GFB > or = BFB > CFB), whereas NADH cytochrome c reductase activity was increased by GFB. Nevertheless, the magnitude of changes were lower than those observed in elongation activities. 4. Treatment with fibrates did not produce peroxisomal proliferation in guinea-pigs, as measured by peroxisomal beta-oxidation activity and liver weight/body weight ratio. Nevertheless, fibrates provoked a reduction in plasma cholesterol and triglycerides, at least in GFB- and BFB-treated animals. 5. Fatty acid elongation was significantly modified by GFB treatment in vivo. The remaining enzyme activities studied were only slightly changed by fibrate treatment. 6. Treatment with BFB and to a lesser extent with CFB, increased the relative proportion of MUFA (palmitoleic and oleic acids) in microsomal phospholipids, whereas PUFA (mainly linoleic acid) decreased. GFB behaved differently, increasing palmitic and linoleic acids and decreasing stearic and oleic acids. The latter changes are attributable to an inhibition of elongation activity by GFB. 7. The changes observed after fibrate treatment in both rats and guinea-pigs, as they are not directly related to peroxisome proliferation, could be more reliably extrapolated to man than those observed only in rats.
Collapse
Affiliation(s)
- M Vázquez
- Dept. Farmacologia y Quimica Terapeutica, Facultad de Farmacia, Núcleo Universitario de Pedralbes, Barcelona, Spain
| | | | | | | | | | | | | |
Collapse
|
9
|
Vázquez M, Muñoz S, Alegret M, Adzet T, Merlos M, Laguna JC. Differential effects of fibrates on the acyl composition of microsomal phospholipids in rats. Br J Pharmacol 1995; 116:2067-75. [PMID: 8640347 PMCID: PMC1908928 DOI: 10.1111/j.1476-5381.1995.tb16413.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
1. The time-course and comparative effects of treatment with clofibrate (CFB), bezafibrate (BFB), and gemfibrozil (GFB) on the acyl composition of the main microsomal phospholipids, i.e. phosphatidylcholine and phosphatidylethanolamine, have been studied in male Sprague-Dawley rats. 2. The administration of the three fibrates caused a strong peroxisomal induction and a hypolipidaemic effect. Concerning the changes in acyl composition, CFB and BFB behaved in a similar way, with differences which could be attributed to their different potency as peroxisome inducers, whereas GFB showed a somewhat distinct profile. 3. The three drugs increased the relative content of palmitic, palmitoleic and oleic acids, whereas the levels of stearic acid and also those of long chain, highly unsaturated fatty acids docosatetraenoic, docosapentaenoic and docosahexaenoic acids were reduced. In general, these effects appeared from the first day of treatment and were highly correlated with peroxisomal proliferation. In addition, they were more evident in the phosphatidylcholine than in the phosphatidylethanolamine fraction. 4. Fibrates increased total monounsaturated fatty acids, whereas a decrease in total polyunsaturated fatty acids in the phosphatidylcholine fraction was observed in CFB- and BFB-, but not in GFB-treated rats. Clear differences appeared between CFB and BFB on the one hand, and GFB on the other when the influence of fibrate treatment on the molar percentages of linoleic, eicosatrienoic, arachidonic and mead acids was analyzed. 5. GFB increased linoleic acid content in phosphatidylethanolamine, whereas CFB and BFB decreased its level in both phospholipid fractions. In contrast, CFB and BFB enhanced eicosatrienoic and mead acids in both fractions and arachidonic acid in phosphatidylethanolamine, whereas GFB had practically no effect.
Collapse
Affiliation(s)
- M Vázquez
- Dept. Farmacología y Química Terapeutica, Facultad de Farmacia, Núcleo Universitario de Pedralbes, Barcelona, Spain
| | | | | | | | | | | |
Collapse
|
10
|
Alegret M, Cerqueda E, Ferrando R, Vázquez M, Sánchez RM, Adzet T, Merlos M, Laguna JC. Selective modification of rat hepatic microsomal fatty acid chain elongation and desaturation by fibrates: relationship with peroxisome proliferation. Br J Pharmacol 1995; 114:1351-8. [PMID: 7606338 PMCID: PMC1510293 DOI: 10.1111/j.1476-5381.1995.tb13355.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
1. The time-course of the effect of clofibrate (CFB), bezafibrate (BFB) and gemfibrozil (GFB) on lipid plasma levels and palmitoyl-, palmitoleoyl- and gamma-linolenoyl-CoA elongase, delta-9, delta-6 and delta-5 desaturase activities, and microsomal electron transport chains, as well as the correlation with the peroxisomal proliferation phenomenon have been studied in male Sprague-Dawley rats. 2. As reported in our previous work, the three drugs behave as peroxisomal proliferators (the order of potency was BFB > CFB > or = GFB) and induced a clear reduction in both plasma cholesterol and triglyceride levels. 3. Palmitoyl-CoA elongation activity was increased by the three drugs (BFB = GFB > CFB), whereas palmitoleoyl-CoA elongation activity was only enhanced by GFB. Elongation activity was not modified by fibrates when gamma-linolenoyl-CoA was used as substrate. These results are in accordance with the existence of three different elongation systems for saturated, mono- and polyunsaturated fatty acids. 4. delta-9, delta-6 and delta-5 desaturase activities were increased by the three fibrates, with an order of potency BFB > CFB = GFB for delta-9 and delta-5, and GFB > BFB = CFB for delta-6. 5. Of the enzyme activities integrated in the microsomal electron transport chains, NADH cytochrome b5 reductase was not affected by fibrate treatment, NADPH cytochrome c reductase activity was enhanced (BFB = GFB > CFB), whereas NADH cytochrome c reductase activity was reduced by CFB and BFB. 6. The increase in Delta-9 and Delta-5 desaturase activities was highly dependent on the peroxisomal proliferation phenomena, whereas the increase in Delta-6 desaturase activity and the decrease in NADH cytochromec reductase was mainly independent. The modifications of palmitoyl-CoA elongase and NADPH cytochrome c reductase activities, as well as plasma lipid levels, were partially correlated with peroxisomal beta-oxidation, but the r2 values obtained point to the existence of additional independent mechanisms.7. As man is assumed to be a species refractory to peroxisomal proliferation, only those fibrate effectsnot absolutely related to this phenomenon are expected to appear after fibrate therapy.
Collapse
Affiliation(s)
- M Alegret
- Dept. Farmacología y Química Terapeutica, Facultad de Farmacia, Núcleo Universitario de Pedralbes, Barcelona, Spain
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Alegret M, Ferrando R, Vázquez M, Adzet T, Merlos M, Laguna JC. Relationship between plasma lipids and palmitoyl-CoA hydrolase and synthetase activities with peroxisomal proliferation in rats treated with fibrates. Br J Pharmacol 1994; 112:551-6. [PMID: 7915611 PMCID: PMC1910384 DOI: 10.1111/j.1476-5381.1994.tb13109.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
1. The time-course of the effect of clofibrate (CFB), bezafibrate (BFB) and gemfibrozil (GFB) on lipid plasma levels and palmitoyl-CoA hydrolase and synthetase activities, as well as the correlations with the peroxisomal proliferation phenomenon have been studied in male Sprague-Dawley rats. 2. The administration of the three drugs caused a significant reduction in body weight gain, accompanied with a paradoxical increase in food intake in groups treated with BFB and GFB. 3. Drug treatment produced gross hepatomegaly and increase in peroxisomal beta-oxidation, and these parameters were strongly correlated. The order of potency was BFB > CFB > or = GFB. 4. Both plasma cholesterol (BFB approximately CFB > GFB) and triglyceride (BFB approximately GFB > CFB) levels were reduced in treated animals. There was an inverse correlation between these parameters and peroxisomal beta-oxidation, although the peroxisomal proliferation seemed to explain only a small part of the hypolipidemic effect observed. 5. Cytosolic and microsomal (but not mitochondrial) palmitoyl-CoA hydrolase activities were increased by the three drugs (BFB > CFB > GFB), probably by inducing the hydrolase I isoform, which is insensitive to inhibition by fibrates in vitro. The increased hydrolase activities were directly and strongly correlated with peroxisomal beta-oxidation. 6. Palmitoyl-CoA synthetase activity was also increased by the treatment with fibrates (BFB > CFB > GFB), probably as a consequence of the enhancement of hydrolase activities. 7. Some of the effects of fibrate treatment can be explained, at least in part, in terms of peroxisomal induction and caution should be exercised in the extrapolation of these results to species, such as man,that are insensitive to peroxisomal proliferation.
Collapse
Affiliation(s)
- M Alegret
- Dept. Farmacología y Química Terapeutica, Facultad de Farmacia, Núcleo Universitario de Pedralbes, Barcelona, Spain
| | | | | | | | | | | |
Collapse
|