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Mornagui B, Rezg R, Repond C, Pellerin L. Bisphenol S favors hepatic steatosis development via an upregulation of liver MCT1 expression and an impairment of the mitochondrial respiratory system. J Cell Physiol 2022; 237:3057-3068. [PMID: 35561261 DOI: 10.1002/jcp.30771] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/05/2022] [Accepted: 04/25/2022] [Indexed: 12/13/2022]
Abstract
Bisphenol S (BPS) is a common substitute of bisphenol A (BPA). Recent data suggest that BPS acts as an obesogenic endocrine disruptor with emerging implications in the physiopathology of metabolic syndrome. However, the effects of BPS on monocarboxylate transporters (acting as carriers for lactate, pyruvate, and ketone bodies) and the mitochondrial respiratory system in the liver remain limited. For this purpose, male Swiss mice were treated with BPS at 100 µg/kg/day for 10 weeks, in drinking water. An increase in body weight and food intake was observed with no increase in locomotor activity. Moreover, data show that BPS increases hepatic MCT1 (a key energetic fuel transporter) mRNA expression accompanied by hepatic steatosis initiation and lipid accumulation, while disrupting mitochondrial function and oxidative stress parameters. Furthermore, BPS produced a significant increase in lactate dehydrogenase and creatine kinase activities. We can suggest that BPS contributes to hepatic steatosis in mice by upregulating monocarboxylate transporters and affecting the bioenergetic status characterized by an impaired mitochondrial respiratory system. Thus, our data highlight a new mechanism putatively implicated in hepatic steatosis development during BPS-induced obesity involving lactate metabolism.
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Affiliation(s)
- Bessem Mornagui
- Faculty of Sciences of Gabes, University of Gabes, Gabes, Tunisia
| | - Raja Rezg
- Higher Institute of Biotechnology of Monastir, University of Monastir, Monastir, Tunisia
| | - Cendrine Repond
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Luc Pellerin
- Department of Physiology, University of Lausanne, Lausanne, Switzerland.,Inserm U1313, Faculté de Médecine et de Pharmacie, Université et CHU de Poitiers, Poitiers Cedex, France
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2
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Schutkowski A, Max D, Bönn M, Brandsch C, Grundmann SM, Hirche F, Staege MS, Stangl GI. Vitamin D Does Not Play a Functional Role in Adipose Tissue Development in Rodent Models. Mol Nutr Food Res 2018; 62. [PMID: 29205876 DOI: 10.1002/mnfr.201700726] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/26/2017] [Indexed: 11/06/2022]
Abstract
SCOPE Several studies have proposed a role of vitamin D in adipogenesis. Here, we sought to study the impact of the vitamin D receptor (Vdr) on adipocyte size in young and old mice and the effect of maternal vitamin D deficiency on fetal adipogenesis. METHODS AND RESULTS Histological analysis of adipose tissues shows that Vdr knockout (KO) mice have smaller adipocytes than wild-type (WT) mice. Next, we compare young and old Vdr-KO and WT mice and find no differences in adipocyte sizes between weaned Vdr-KO and WT mice. However, 1-year-old Vdr-KO mice, suffering from alopecia, have smaller-sized adipocytes than WT mice, although they consume more food. To elucidate whether vitamin D can directly impact adipocyte development at a critical stage of adipogenesis, we feed rat dams a vitamin D deficient (0 IU kg-1 ) or vitamin D adequate (1000 IU kg-1 ) diet. Neither DNA microarray analysis of the adipose tissues of the newborn rats nor the adipocyte sizes of 21-day-old offspring show significant differences between the two groups. CONCLUSION Data indicate that vitamin D does not play a fundamental role in adipogenesis because vitamin D does not affect fetal adipogenesis. Moreover, the smaller adipocytes observed in adult Vdr-KO mice are presumably caused by an increased energy expenditure due to alopecia.
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Affiliation(s)
- Alexandra Schutkowski
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Daniela Max
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Markus Bönn
- Department of Soil Ecology, UFZ Helmholtz Centre for Environmental Research, Halle (Saale), Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Corinna Brandsch
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Sarah M Grundmann
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Frank Hirche
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Martin S Staege
- University Clinic and Polyclinic for Child and Adolescent Medicine, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Gabriele I Stangl
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
- Competence Cluster of Cardiovascular Health and Nutrition (nutriCARD), Halle-Jena-Leipzig, Germany
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Radtke J, Geissler S, Schutkowski A, Brandsch C, Kluge H, Duranti MM, Keller S, Jahreis G, Hirche F, Stangl GI. Lupin protein isolate versus casein modifies cholesterol excretion and mRNA expression of intestinal sterol transporters in a pig model. Nutr Metab (Lond) 2014; 11:9. [PMID: 24490902 PMCID: PMC3922606 DOI: 10.1186/1743-7075-11-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 01/28/2014] [Indexed: 11/26/2022] Open
Abstract
Background Lupin proteins exert hypocholesterolemic effects in man and animals, although the underlying mechanism remains uncertain. Herein we investigated whether lupin proteins compared to casein modulate sterol excretion and mRNA expression of intestinal sterol transporters by use of pigs as an animal model with similar lipid metabolism as humans, and cellular cholesterol-uptake by Caco-2 cells. Methods Two groups of pigs were fed cholesterol-containing diets with either 230 g/kg of lupin protein isolate from L. angustifolius or 230 g/kg casein, for 4 weeks. Faeces were collected quantitatively over a 5 d period for analysis of neutral sterols and bile acids by gas chromatographically methods. The mRNA abundances of intestinal lipid transporters were analysed by real-time RT-PCR. Cholesterol-uptake studies were performed with Caco-2 cells that were incubated with lupin conglutin γ, phytate, ezetimibe or albumin in the presence of labelled [4-14C]-cholesterol. Results Pigs fed the lupin protein isolate revealed lower cholesterol concentrations in total plasma, LDL and HDL than pigs fed casein (P < 0.05). Analysis of faeces revealed a higher output of cholesterol in pigs that were fed lupin protein isolate compared to pigs that received casein (+57.1%; P < 0.05). Relative mRNA concentrations of intestinal sterol transporters involved in cholesterol absorption (Niemann-Pick C1-like 1, scavenger receptor class B, type 1) were lower in pigs fed lupin protein isolate than in those who received casein (P < 0.05). In vitro data showed that phytate was capable of reducing the uptake of labelled [4-14C]-cholesterol into the Caco-2 cells to the same extend as ezetimibe when compared to control (−20.5% vs. −21.1%; P < 0.05). Conclusions Data reveal that the cholesterol-lowering effect of lupin protein isolate is attributable to an increased faecal output of cholesterol and a reduced intestinal uptake of cholesterol. The findings indicate phytate as a possible biofunctional ingredient of lupin protein isolate.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Gabriele I Stangl
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 2, 06120 Halle (Saale), Germany.
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4
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Singla N, Dhawan D. Zinc protection against aluminium induced altered lipid profile and membrane integrity. Food Chem Toxicol 2013; 55:18-28. [DOI: 10.1016/j.fct.2012.12.047] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Revised: 12/25/2012] [Accepted: 12/27/2012] [Indexed: 12/14/2022]
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Gomez NN, Biaggio VS, Rozzen EJ, Alvarez SM, Gimenez MS. Zn-limited diet modifies the expression of the rate-regulatory enzymes involved in phosphatidylcholine and cholesterol synthesis. Br J Nutr 2007; 96:1038-46. [PMID: 17181878 DOI: 10.1017/bjn20061951] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Suboptimal intake of Zn is one of the most common nutritional worldwide problems. Previously, we showed that Zn deficiency produces alterations in lung lipid metabolism in rats. We studied the effect of a Zn-limited (ZL) diet on the expression of the enzymes involved in phosphatidylcholine and cholesterol synthesis. After 2 months of treatment with a ZL diet we found important variations in the lipid content of Wistar male rats: triacylglycerol (TG) decreased 60% (P<0.001) while esterified cholesterol (EC), free cholesterol and phospholipids (PL) increased 66%, 24 % and 25% respectively. We also observed a decrease of 40 % in the amount of (3)H incorporated into TG and an increase of 47% and 28% in the (3)H incorporated to PL and EC respectively. Fatty acid synthase and glucose-6-phosphate dehydrogenase activity was increased (P<0.01 and P<0.05 respectively). Glycerol-3-phosphate acyltransferase, lipoprotein lipase, diacyl glycerol acyl transferase and 3-hydroxy-3-methylglutaryl CoA reductase expression decreased (P<0.01 in all cases), while acetyl CoA carboxylase and cholinephosphate cytidylyltransferase increased (P<0.01 and P<0.005 respectively). These results suggest that ZL alters the expression of enzymes involved in phosphatidylcholine and cholesterol synthesis, which could lead to increased PL and cholesterol and decreased TG. This study suggests that major changes in the lipid composition of lung are induced by a ZL condition. Therefore, Zn deficiency must be taken into account in order to design therapies and public health interventions, such as Zn supplementation for high-risk subjects or certain diseases, such as asthma.
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Affiliation(s)
- Nidia Noemí Gomez
- Departamento de Bioquímica y Ciencias Biológicas, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina
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tom Dieck H, Döring F, Fuchs D, Roth HP, Daniel H. Transcriptome and proteome analysis identifies the pathways that increase hepatic lipid accumulation in zinc-deficient rats. J Nutr 2005; 135:199-205. [PMID: 15671213 DOI: 10.1093/jn/135.2.199] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
For identification of the underlying molecular changes in hepatic lipid metabolism in zinc deficiency, rats were force-fed a zinc-deficient diet. Subsequently DNA-microarray and proteome profiling was performed in combination with hepatic lipid analysis. Of 6200 target sequences analyzed, 268 transcripts showed altered expression levels in livers of zinc-deficient rats, with 43 genes thereof related to hepatic lipid metabolism. Northern blot analysis and quantitative real-time RT-PCR were employed to confirm changes in mRNA levels. Proteins involved in lipid metabolism were identified by proteome analysis. Functional gene clusters with uniform changes in transcript levels suggested that the pathways required for lipolysis and mitochondrial as well as peroxisomal fatty acid degradation were downregulated, whereas those needed for de novo fatty acid synthesis and triglyceride assembly were increased. Subsequent enzymatic analysis of liver tissues confirmed an almost 40% greater triacylglycerol concentration in zinc-depleted rats, as well as an altered fatty acid composition of the lipid fraction as determined by gas chromatography. Liver lipids of zinc-deficient rats had significantly greater proportions of cis-9-oleic acid, cis-11-vaccenic acid, caprylic acid, myristic acid, alpha-linolenic acid, and eicosapentaenoic acid, and significantly less stearic and arachidonic acids. These alterations in hepatic metabolism are discussed in the context of changes in mRNA and protein levels of enzymes and transporters responsible for fatty acid metabolism, sequestration, and their transcriptional control.
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Affiliation(s)
- Heike tom Dieck
- Degussa Food Ingredients GmbH, Lise-Meitner-Strasse 34, 85354 Freising, Germany
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Daniel H, tom Dieck H. Nutrient-gene interactions: a single nutrient and hundreds of target genes. Biol Chem 2004; 385:571-83. [PMID: 15318805 DOI: 10.1515/bc.2004.071] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
AbstractBased on the effects of a selective experimental zinc deficiency in a rodent model we explore the use of transcriptome profiling for assessing nutrient-gene interactions in the liver at the molecular and cellular levels. Zinc deficiency caused pleiotropic alterations in mRNA/protein levels of hundreds of genes. In the context of observed metabolic alterations in hepatic metabolism, possible mechanisms are discussed for how a low zinc status may be sensed and transmitted into changes in various metabolic pathways. However, it also becomes obvious that analysis of such complex nutrient-gene interactions beyond the descriptional level is a real challenge for systems biology.
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Affiliation(s)
- Hannelore Daniel
- Molecular Nutrition Unit, Technical University of Munich, Life and Food Science Center, Hochfeldweg 2, D-85350 Freising-Weihenstephan, Germany.
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8
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Abstract
There have been a limited number of studies investigating surfactant lipid changes in lung with trace elements. The present investigation was designed to examine the effect of moderate zinc deficiency on the lipid metabolism in rat lung. We also evaluated whether zinc deficiency, which is a wide-spread problem, could play a role in adult respiratory distress syndrome (ARDS). For that purpose, adult male Wistar rats were fed two diets differing in zinc concentration. The rats were divided into two groups. One group was fed a zinc-deficient diet containing 3 mg Zn/kg, and the other group received a zinc-adequate control diet with 30 mg Zn/kg according to AIN 93-M. After 2 mon of treatment, we observed that in the zinc-deficient group (i) total lipids, phospholipids, and cholesterol increased whereas TG decreased in whole lung; (ii) phospholipid (PC) concentration increased in lamellar bodies and alveolar macrophages and decreased in extracellular surfactant but did not change in microsomes; (iii) protein concentration decreased in whole lung, extracellular surfactant, lamellar bodies, and macrophages; (iv) the incorporation of [Me-14C]choline into PC (phospholipids) of lung slices increased; and (v) the activity of CTP/phosphocholine cytidylyltransferase bound to the microsomes increased in the lung. These results suggest that the lipid concentration in the lung (especially the phospholipids) is modified directly or indirectly by a zinc-deficient diet. In a zinc-deficient diet, the lung changes the pattern of PC for an adaptive or recovery stage. Therefore, zinc deficiency implications are important for the design of therapies and public health interventions involving targeted zinc supplementation for high-risk groups or groups with certain diseases, such as ARDS.
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Affiliation(s)
- N N Gomez
- Department of Biochemistry and Biological Sciences, Faculty of Chemistry, Biochemistry and Pharmacy, National University of San Luis, Argentina
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Wauben IP, Xing HC, Wainwright PE. Neonatal dietary zinc deficiency in artificially reared rat pups retards behavioral development and interacts with essential fatty acid deficiency to alter liver and brain fatty acid composition. J Nutr 1999; 129:1773-81. [PMID: 10498747 DOI: 10.1093/jn/129.10.1773] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The objective of this study was to investigate whether short-term zinc deficiency in the early neonatal period would exacerbate the effects of essential fatty acid (EFA) deficiency on liver and brain long-chain polyunsaturated fatty acid (LCPUFA) composition, as well as on behavioral development in artificially reared rat pups. Using a 2 x 2 factorial design, male Long-Evans rat pups were reared artificially from postnatal d 5 to 16; pups were fed through gastrostomy tubes with rat formula deficient in zinc and/or EFA. As expected, EFA deficiency significantly reduced levels of arachidonic acid [AA, 20:4(n-6)] and docosahexanoic acid [DHA, 22:6(n-3)] in liver phosphatidylcholine (PC) and brain phosphaditylethanolamine (PE), and increased 22:5(n-6) levels in liver and brain PC and PE. There were significant interactions between zinc and EFA in liver such that zinc deficiency reduced AA and DHA in the EFA-adequate groups, but significantly increased AA in the EFA-deficient groups. Contrary to the hypothesis, short-term zinc deficiency did not exacerbate the effects of EFA deficiency in liver phospholipids. In brain PE, a significant interaction between EFA and zinc was observed such that zinc deficiency increased 22:5(n-6) concentrations in EFA-adequate but not in EFA-deficient groups. Regardless of their EFA status, zinc-deficient rats were growth retarded and demonstrated deficits in locomotor skills. Possible effects of long-term zinc and EFA deficiency on brain function should be investigated in future studies.
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Affiliation(s)
- I P Wauben
- Department of Health Studies and Gerontology, University of Waterloo, Waterloo, ON, Canada N2L 3G1
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Villet A, Ravel A, Richard MJ, Alary J, Roussel AM, Favier A. Fish oil effects on tissular fatty acids and plasma lipid peroxidation in zinc deficient rats. J Trace Elem Med Biol 1997; 11:223-31. [PMID: 9575473 DOI: 10.1016/s0946-672x(97)80017-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Zinc has been reported to play a key role in lipid metabolism as well as in defences against oxidative stress. The aim of this work was to investigate the fatty acid distribution (plasma, heart, kidney, liver) and peroxidation (plasma) in zinc-deficient rats fed with n-6 fatty acids (10% corn oil) or n3 fatty acid fish oil (10% Maxepa). Zinc deficiency led to a decreased tissular and plasma n-6/n-3 ratio both in triglycerides and phospholipids. This effect was more marked in the Maxepa group than in the corn oil group. In plasma, the TBARs/TG + PL ratio was significantly enhanced in zinc-deficient animals, especially in rats receiving Maxepa. With regard to these results, zinc deficiency could appear as an aggravating factor of oxidative risk when associated with a n-3 fatty acid-rich diet. This work draws attention to the harmful oxidative risk associated with patients' intake of fish oil concentrate, without taking into account their antioxidant dietary intakes and status.
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Affiliation(s)
- A Villet
- Grepo, UFR de Pharmacie, La Tronche, France
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Eder K, Kirchgessner M. Concentrations of lipids in plasma and lipoproteins and oxidative susceptibility of low-density lipoproteins in zinc-deficient rats fed linseed oil or olive oil. J Nutr Biochem 1997. [DOI: 10.1016/s0955-2863(97)00057-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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Stangl G, Kirchgessner M. EFFECT OF NICKEL DEFICIENCY ON FATTY ACID COMPOSITION OF TOTAL LIPIDS AND INDIVIDUAL PHOSPHOLIPIDS IN BRAIN AND ERYTHROCYTES OF RATS. Nutr Res 1997. [DOI: 10.1016/s0271-5317(96)00240-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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13
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Eder K, Kirchgessner M. Zinc deficiency and the desaturation of linoleic acid in rats force-fed fat-free diets. Biol Trace Elem Res 1996; 54:173-83. [PMID: 8886317 DOI: 10.1007/bf02786264] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Recent studies with rats force-fed zinc-deficient diets containing various types of fat failed to demonstrate a role of zinc in desaturation of linoleic acid. The present study was conducted to investigate the effect of zinc deficiency on desaturation of linoleic acid in rats that were initially force-fed fat-free diets to stimulate activity of desaturases. Therefore, rats were fed zinc-adequate and zinc-deficient fat-free diets for 6 d. After that period, the groups were divided and half of the rats continued feeding the fat-free diet for another 3.5 d whereas the other half was switched to a fat diet by supplementing the fat-free diet with 5% safflower oil. In order to assess desaturation of linoleic acid, fatty acid compositions of liver phosphatidylcholine, -ethanolamine, and -serine were considered, particularly levels of individual (n-6) polyunsaturated fatty acids (PUFA). Levels of total and individual (n-6) PUFA were similar in zinc-adequate and zinc-deficient rats fed the fat-free diet throughout the experiment. Addition of 5% safflower oil increased levels of total and individual (n-6) PUFA in both zinc-adequate and zinc-deficient rats. However, total (n-6) PUFA in all types of phospholipids were higher in zinc-adequate rats than in zinc-deficient rats. Additionally, in zinc-deficient rats there were changes of (n-6) PUFA levels typical for impaired delta 5 and delta 6 desaturation: linoleic acid and dihomo-gamma-linolenic acid were elevated; arachidonic acid, docosatetraenoic acid, and docosapentaenoic were lowered by zinc deficiency. Therefore, the study shows that zinc deficiency impairs desaturation of linoleic acid in rats force-fed fat-free diets and therefore supports results from former convential zinc deficiency experiments suggesting a role of zinc for desaturation of linoleic acid.
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Affiliation(s)
- K Eder
- Institut für Ernährungsphysiologie der Technischen, Universität München, Freising, Germany
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15
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Eder K, Kirchgessner M. The effect of dietary fat on activities of lipogenic enzymes in liver and adipose tissue of zinc-adequate and zinc-deficient rats. J Nutr Biochem 1996. [DOI: 10.1016/0955-2863(96)00008-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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16
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Eder K, Kirchgessner M. Activities of liver microsomal fatty acid desaturases in zinc-deficient rats force-fed diets with a coconut oil/safflower oil mixture of linseed oil. Biol Trace Elem Res 1995; 48:215-29. [PMID: 9398942 DOI: 10.1007/bf02789404] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The present study was conducted to investigate the effect of zinc deficiency on fatty acid desaturation in rats fed two different types of dietary fat, a mixture of coconut oil and safflower oil (7:1, w/w, "coconut oil diet") or linseed oil ("linseed oil diet"). In order to ensure an adequate food intake, all rats were force-fed by gastric tube. Zinc deficiency caused statistical significant reduction of delta 9-desaturase activity in liver microsomes of rats fed coconut oil diet and tendencial reduction (p < 0.15) in rats fed linseed oil diet compared with control rats fed diets with the same type of fat. In agreement with this effect, zinc deficiency in the rats fed both types of dietary fat increased the ratio between total saturated and total monounsaturated fatty in liver phospholipids and liver microsomes. Zinc deficient rats on the coconut oil diet had unchanged delta 6-desaturase activity with linoleic acid as substrate and lowered activity with alpha-linolenic acid as substrate. In contrast, zinc deficient rats on the linseed oil diet had increased delta 6-desaturase activity with linoleic acid as substrate and unchanged activity with alpha-linolenic acid. Because linoleic acid is the main substrate for delta 6-desaturase in the rats fed coconut oil diet, and alpha-linolenic acid is the main substrate in the rats fed linseed oil diet, it is concluded that in vivo delta 6-desaturation was not changed by zinc deficiency in the rats fed both types of dietary fat. Activity of delta 5-desaturase was also not changed by zinc deficiency in the rats fed both dietary fats. Levels of fatty acids in liver phospholipids and microsomes derived by delta 4-, delta 5-, and delta 6-desaturation were not consistently changed by zinc deficiency in the rats fed both types of dietary fat. Thus, the enzyme studies and also fatty acid composition data of liver phospholipids and microsomes indicate that zinc deficiency does not considerably disturb desaturation of linoleic and alpha-linolenic acid. Therefore, it is suggested that similarities between deficiencies of zinc and essential fatty acids described in literature are not due to disturbed desaturation of linoleic acid in zinc deficiency. The present study also indicates that zinc deficiency enhances incorporation of eicosapentaenoic acid into phosphatidylcholine of rats fed diets with large amounts of n-3 polyunsaturated fatty acids.
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Affiliation(s)
- K Eder
- Institut für Ernährungsphysiologie, Technischen Universität München-Weihenstephan, Freising, Germany
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Eder K, Kirchgessner M. Zinc deficiency and activities of lipogenic and glycolytic enzymes in liver of rats fed coconut oil or linseed oil. Lipids 1995; 30:63-9. [PMID: 7760690 DOI: 10.1007/bf02537043] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In previous studies, zinc-deficient rats force-fed a diet with coconut oil as the major dietary fat developed a fatty liver, whereas zinc-deficient rats force-fed a diet with linseed oil did not. The present study was conducted to elucidate the reason for this phenomenon. In a bifactorial experiment, rats were fed zinc-adequate or zinc-deficient diets containing either a mixture of coconut oil (70 g/kg) and safflower oil (10 g/kg) ("coconut oil diet") or linseed oil (80 g/kg) ("linseed oil diet") as a source of dietary fat, and activities of lipogenic and glycolytic enzymes in liver were determined. In order to ensure adequate food intake, all the rats were force-fed. Zinc-deficient rats on the coconut oil diet developed a fatty liver, characterized by elevated levels of triglycerides with saturated and monounsaturated fatty acids. These rats also had markedly elevated activities of the lipogenic enzymes acetyl-CoA carboxylase, fatty acid synthase (FAS), glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), and citrate cleavage enzyme, whereas activities of malic enzyme and glycolytic enzymes were not different compared with zinc-adequate rats on the coconut oil diet. In contrast, rats receiving the linseed oil diet had similar triglyceride concentrations regardless of zinc status, and activities of lipogenic enzymes and glycolytic enzymes were not different between the two groups. Zinc-deficient rats fed either type of dietary fat exhibited statistically significant correlations between activities of FAS, G6PDH, 6PGDH and concentrations of saturated and monounsaturated fatty acids in liver.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- K Eder
- Institut für Ernährungsphysiologie der Technischen Universität München, Freising, Germany
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