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At least 1,063 records · Page 59Linked to original sources
PubMed1993

Inhibition of lipogenesis in rat brown adipose tissue by clofibrate.

The effect of clofibrate (Atromid S, ethyl-2-(4-chlorophenoxy)-2-methylpropionate) administration for 7 days to rats on lipogenesis and on some lipogenic enzyme activities in brown adipose tissue (BAT), liver and white adipose tissue (WAT) was examined. As compared to control rats the rate of lipogenesis in BAT in the clofibrate-treated animals was significantly decreased. The rate of liver lipogenesis increased slightly, whereas lipogenesis in the WAT was not affected by clofibrate. In BAT, the drug treatment resulted in depression of fatty acid synthase, ATP-citrate lyase, malic enzyme, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities. The activity of liver fatty acid synthase did not change, ATP-citrate lyase activity slightly decreased, whereas the activity of malic enzyme significantly increased in this organ after clofibrate feeding. The ATP-citrate lyase activity in WAT decreased, while fatty acid synthase and other lipogenic enzymes were not changed after clofibrate feeding. Clofibrate treatment did not influence the activity of NADP-linked isocitrate dehydrogenase and malate dehydrogenase (enzymes not linked directly to lipogenesis), either in BAT, liver or WAT. The data presented suggest that the hypolipidaemic effect of clofibrate in the rat may be due (possibly among other mechanisms) to reduction of the rate of fatty acid synthesis in BAT but not in the liver and WAT.

Adipose Tissue↗
PubMed1986

Effect of dietary medium chain triglyceride on lipogenic enzyme activity in rat liver.

This study was conducted to confirm that medium chain triglyceride (MCT) feeding itself would increase hepatic lipogenic enzyme activity without causing a lack of essential fatty acids (EFA) in the liver. Male weaning rats were fed for 11 weeks on diets containing 2% corn oil and 13% various fats: MCT, corn oil, tripalmitin or beef tallow, respectively. MCT feeding was clearly shown to increase the activities of fatty acid synthetase (FAS) and malic enzyme (ME) in the liver. Rats weighing 170 g were pair-fed for 7 days on diets containing 15% MCT, 13% MCT + 2% corn oil, 15% corn oil, and 2% corn oil and no fat (control groups), respectively, under a fixed level of carbohydrate (sucrose). The addition of 2% corn oil to MCT (13%) did not depress these enzyme activities, even though supplementing the fat-free diet with 2% corn oil resulted in a significant decline in the activities. When the rats received various amounts of MCT, the extent to which the degree of FAS and ME activities increased by MCT feeding depended on the amount of MCT in the dietary fat mixture with corn oil. Supplement of over 5% corn oil to MCT diets did not inhibit them sufficiently. In the liver lipids of animals fed MCT, there were no appearances of 20:3 omega 9 (5,8,11-eicosatrienoic acid), but the levels of mono-unsaturated fatty acids were increased by MCT feeding. The results suggest that MCT ingestion itself enhances lipogenic enzyme activity via some metabolic charge.

Animals↗
PubMed1987

Possible role of insulin status in the increased lipogenic enzyme activity by dietary medium-chain triglyceride in rat liver.

The possible role of insulin status in the increase in liver lipogenic enzyme activities upon feeding medium-chain triglyceride (MCT) was investigated with streptozotocin-induced diabetic rats and insulin-treated diabetic rats. Rats were fed synthetic diets that contained either 2% corn oil (control), fat free, 13% MCT +2% corn oil, or 13% lard +2% corn oil, respectively. Feeding the MCT diet for 3 days increased serum ketone bodies in both the normal and diabetic rats. Insulin levels of MCT-fed rats tended to be higher than in normal animals. MCT feeding caused an enhancement of fatty acid synthetase (FAS) and malic enzyme (ME) in the liver of normal rats, whereas diabetic rats failed to register an increase in those activities due to MCT feeding. Administration of insulin to diabetic rats resulted in a recovery of the level of those enzyme activities to about the same degree as in each of the normal rat groups. It was interesting that diabetic MCT-fed rats with insulin treatment maintained higher enzyme activities in comparison to the lard and control groups. These results suggest that the increase in lipogenic enzyme activities caused by dietary MCT is presumably dependent on differences in insulin status.

Animals↗
PubMed2006

Effects of cadmium amendments on low-molecular-weight organic acid exudates in rhizosphere soils of tobacco and sunflower.

To recognize physiological response of plants to cadmium (Cd) toxicity in rhizosphere of plants, the pot experiments were employed to investigate how low-molecular-weight organic acids (LMWOAs) were exudated from tobacco and sunflower roots of Cd-amended soils. The aims of this study were to assess the effect of LMWOAs on uptake of Cd by tobacco and sunflower under pot experiments, thus comparing the ability of tobacco and sunflower for phytoremediation. Surface soils (0-20 cm) were collected from Taichung Experiment Station (TC) (silty loam). Cadmium chloride (CdCl(2)) was amended into TC soil, giving Cd concentrations of 1, 5, 10 mg kg(-1) soil. Soils with different concentrations of Cd were put into 12 cm (i.d.) pots for incubation, and then 2-week-old tobacco and sunflower seedlings were transplanted into the pots. Tobacco and sunflower were grown in greenhouse for 50 days, respectively. The rhizosphere and bulk soils, and fresh plant tissues were collected after harvest. The Cd concentrations in the plant and transfer factor values in the sunflower were higher than that in the tobacco. No LMWOAs were detected by gas chromatograph in bulk soils, and low amounts of LMWOAs were found in uncontaminated rhizosphere soils. Acetic, lactic, glycolic, malic, maleic, and succinic acids were found in the tobacco and sunflower rhizosphere soils. Concentrations of LMWOAs increased with increasing amendment of Cd concentrations in tobacco and sunflower rhizosphere soils. Correlation coefficient (r) of concentrations of Cd amendment versus LMWOAs exudates of tobacco and sunflower were 0.85 and 0.98, respectively. These results suggest that the different levels of LMWOAs present in the rhizosphere soil play an important role in the solubilization of Cd that bound with soil particle into soil solution and then uptake by plants.

Biomass↗
PubMed1991

Identification of heterogeneity in human isolates of Giardia lamblia by isoenzyme studies.

Electrophoretic mobility patterns of six enzymes, viz. alkaline phosphatase E.C. 3.1.3.1., acid phosphatase E.C. 3.1.3.2., malic enzyme E.C. 1.1.1.40., phosphoglucomutase E.C. 2.7.5.1., isocitrate dehydrogenase E.C. 1.1.1.42., glucose-6-phosphate dehydrogenase E.C. 1.1.1.49 of two axenically cultured human Giardia lamblia isolated from India (PD-1 and PD-2) and one strain from Portland, Oregon, USA (P-1) were compared using polyacrylamide gel electrophoresis (PAGE). Based on the difference in the mobility patterns of the enzymes phosphoglucomutase, isocitrate dehydrogenase and malic enzyme, the PD-1 and PD-2 isolates appeared to be quite different from P-1. In the present study, the isocitrate dehydrogenase and alkaline phosphatase enzymes were used for the first time for differentiation of Giardia isolates. In the case of PD-1, two alkaline phosphatase bands could be seen whereas only one band was observed in PD-2 and P-1. Thus, the three strains could be grouped into three different zymodemes. These findings reveal the significant heterogeneity in G. lamblia isolates both from widely separated areas and within a single region. Heterogeneity among G. lamblia strains may explain the variable clinical manifestations, host response and treatment efficacy characteristic of human giardiasis.

Acid Phosphatase↗
PubMed1976

Effects of thyroid hormone deficiency on the distribution of hepatic metabolites and control of pathways of carbohydrate metabolism in liver and adipose tissue of the rat.

1. Measurements have been made of the hepatic metabolites in normal and thyroidectomized rats and enzymes of the glycolytic route, the pentose phosphate pathway, the tricarboxylic acid cycle and lipogenesis together with the flux of glucose through alternative pathways of glucose metabolism and into lipid. 2. There is a significant fall in the content of ADP, AMP, citrate, long-chain acyl-CoA derivatives and a rise of 3-phosphoglycerate, 2-phosphoglycerate and phosphoenolpyruvate following thyroidectomy. The observed changes in the glycolytic intermediates may be correlated with the increased activity of phosphofructokinase relative to pyruvate kinase and fructose bisphosphatase. 3. The NAD+/NADH quotient of the mitochondrial compartment, calculated from the reactants and Keq of 3-hydroxybutyrate dehydrogenase, becomes significantly more oxidized in hypothyroid animals. The redox state of the cytosolic NAD and NADP couples remains relatively unchanged. 4. The changes in the hepatic content of CoA derivatives and citrate and in the mitochondrial redox state are interpreted as indicating a depressed rate of lipid oxidation. 5. Calculations of the compartmentation of metabolites between the cytosol and mitochondria indicate a very marked decrease in mitochondrial citrate, 2-oxoglutarate and glutamate with smaller changes in aspartate and malate. These changes are interpreted as providing evidence for the importance of modifications in the malate-aspartate shuttle in hypothyroidism; this is further supported by measured changes in the distribution and activities of the component enzymes of the hydrogen shuttles. 6. There is a diminished activity of glucokinase and of enzymes of the glycolytic pathway below phosphofructokinase in livers from hypothyroid rats. The oxidative enzymes of the pentose phosphate pathway, ATP-citrate lyase, 'malic' enzyme and fatty acid synthetase also decrease markedly. There is a striking parallelism between the changes of enzyme profile of liver and adipose tissue in hypothyroidism. 7. Adrenal glands from hypothyroid rats showed a generalized delcine in enzyme activity in parallel with the fall in tissue weight. Cytosolic glycerol-3-phosphate dehydrogenase decreased sharply. 8. The present results are discussed in relation to data in the literature on the increased activities of cyclic AMP and cyclic GMP phosphodiesterases in hypothyroidism, observations which integrate the relationships between anabolic and catabolic pathways of carbohydrate and lipid metabolism with alterations in hormone sensitivity in hypothyroidism.

Adenine Nucleotides↗
PubMed1987

Isotope effect studies of the chemical mechanism of nicotinamide adenine dinucleotide malic enzyme from Crassula.

The 13C primary kinetic isotope effect on the decarboxylation of malate by nicotinamide adenine dinucleotide malic enzyme from Crassula argentea is 1.0199 +/- 0.0006 with proteo L-malate-2-H and 1.0162 +/- 0.0003 with malate-2-d. The primary deuterium isotope effect is 1.45 +/- 0.10 on V/K and 1.93 +/- 0.13 on Vmax. This indicates a stepwise conversion of malate to pyruvate and CO2 with hydride transfer preceding decarboxylation, thereby suggesting a discrete oxaloacetate intermediate. This is in agreement with the stepwise nature of the chemical mechanism of other malic enzymes despite the Crassula enzyme's inability to reduce or decarboxylate oxaloacetate. Differences in morphology and allosteric regulation between enzymes suggest specialization of the Crassula malic enzyme for the physiology of crassulacean acid metabolism while maintaining the catalytic events found in malic enzymes from animal sources.

Carbon Isotopes↗
PubMed2006

A fast method for determining low-molecular-mass aliphatic carboxylic acids by high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

A fast quantitative high-performance liquid chromatographic separation method with atmospheric pressure chemical ionization mass spectrometric detection (HPLC-APCI-MS) was developed for the determination of low-molecular-mass aliphatic mono- and dicarboxylic acids typically present in different industrial process waters. A mixture of glycolic, lactic, a-glucoisosaccharinic, oxalic, maleic, fumaric, succinic, malic, glutaric, methylsuccinic, and adipic acids was separated using an RP chromatographic system. Adipic acid was used as an internal standard to calculate correlation coefficients for the acids studied. The chromatographic analysis of these acids was primarily carried out by means of gradient elution with an aqueous formic acid solution (0.15%, pH 2.5) and methanol using a modified C18 stationary phase. Good acid separation could be obtained for all acids by optimizing the chromatographic conditions. The method provides a simple sample preparation and faster analysis time compared to the traditional gas chromatographic methods, thus enabling almost real-time monitoring of these acids. Finally, the method developed was applied to the analysis of a complex mixture of aliphatic hydroxy carboxylic acids, which are formed as alkaline degradation products of carbohydrates during wood delignification and are present in the cooking spent liquor (black liquor).

Atmospheric Pressure↗
PubMed1978

Enzyme histochemical properties of kitten osteoclasts in bone imprint preparations.

The enzyme histochemical characteristics of osteoclasts in imprints of the metaphyseal regions of femurs, from male kittens aged approximately 18 weeks, were investigated. A selected number of enzymes representative of a variety of metabolic pathways were studied. The enzyme profile, time for the first appearance of detectable reaction product, intensity of the reactions, and localization of the reaction products were noted. Osteoclasts are rich in enzymes, and metabolic pathways are well developed in respect of the utilization of the reduced coenzymes NADP and NADPH, succinic, malic, lactic, and isocitric acids, beta-hydroxybutyrate and glucose-6-phosphate, the reactions being mediated by the diaphorases and dehydrogenases. The activities of acid and neutral phosphatases, non-specific esterases, and leucine naphthylamidase were high in these cells. However, little or no activity was demonstrated in respect of glutamate and alpha-glycerophosphate dehydrogenases or of aryl sulphatase, glucose-6-phosphatase and alkaline phosphatase.

Animals↗
PubMed1989

Topical treatment of burns using aserbine.

A cream containing malic, benzoic and salicylic acid esters (Aserbine) was evaluated as a topical dressing for dermal burns. Children with thermal injuries covering less than 20 per cent of the body surface area (BSA) were treated with Aserbine (53 patients), Daromide (31 patients) or silver sulphadiazine (SSD) (16 patients). In these groups, hot liquids were the cause of injury in 92 per cent, 100 per cent and 80 per cent of patients respectively. There were no significant differences in the numbers of patients with clinical evidence of infection. Aserbine did not inhibit the growth of staphylococci or Ps. aeruginosa, partly inhibited beta-haemolytic streptococci and Proteus sp., and completely inhibited the growth of E. coli. The rate of wound healing did not differ significantly between the groups. No toxic effects of Aserbine were observed, apart from transient discomfort on application. Aserbine is a safe, inexpensive topical agent suitable for thermal burns which are not heavily contaminated.

Anti-Infective Agents, Local↗
PubMed1995

Different regulatory properties of the cytosolic and mitochondrial forms of malic enzyme isolated from human brain.

The human brain contains a cytosolic and mitochondrial form of NADP(+)-dependent malic enzyme. To investigate their possible metabolic roles we compared the regulatory properties of these two iso-enzymes. The mitochondrial malic enzyme exhibited a sigmoid substrate saturation curve at low malate concentration which was shifted to the right at both higher pH values and in the presence of low concentration of Mn2+ or Mg2+. Succinate or fumarate increased the activity of the mitochondrial malic enzyme at low malate concentration. Both activators shifted the plot of reaction velocity versus malate concentration to the left, and removed sigmoidicity, but the maximum velocity was unaffected. The activation was associated with a decrease in Hill coefficient from 2.3 to 1.1. The human brain cytosolic malic enzyme displayed a hyperbolic substrate saturation kinetics and no sigmoidicity was detected even at high pH and low malate concentrations. Succinate or fumarate exerted no effect on the enzyme activity. Excess of malate inhibited the oxidative decarboxylation catalysed by cytosolic enzyme at pH 7.0 and below. In contrast, decarboxylation catalysed by mitochondrial malic enzyme, was unaffected by the substrate. These results suggest that under in vivo conditions, cytosolic malic enzyme catalyses both oxidative decarboxylation of malate and reductive carboxylation of pyruvate, whereas the role of mitochondrial enzyme is limited to decarboxylation of malate. One may speculate that in vivo the reaction catalysed by cytosolic malic enzyme supplies dicarboxylic acids (anaplerotic function) for the formation of neurotransmitters, while the mitochondrial enzyme regulates the flux rate via Krebs cycle by disposition of the tricarboxylic acid cycle intermediates (cataplerotic function).

Brain↗
PubMed1999

The age-related changes in lipogenic enzymes: the role of dietary factors and thyroid hormone responsiveness.

To determine whether resistance to insulin or to thyroid hormones rather than an inherent defect in enzyme activity expression account for the age-related changes in lipogenic enzymes, the activities of malic enzymes (ME), fatty acid synthase (FAS), glucose-6-phosphate dehydrogenase (G-6PD) and 6-phosphogluconate dehydrogenase (6-PGD) were assayed in hepatic, retroperitoneal fat and epididymal fat cytosol of male Fischer 344 rats at 3.5, 12 and 25 months of age. The rats were maintained on either regular rat chow with 62% of calories as complex carbohydrates or were given either high glucose or fructose diet with 65.7% of calories provided by glucose or fructose respectively. Additional groups of young and aged rats were treated with L-triiodothyronine (T3) (15 microg/100 g body weight) for 10 days. Treatment with T3 resulted in higher levels of hepatic ME activity regardless of the diet consumed or the age of the rats. T3 had no consistent effect on FAS, G-6PD or 6-PGD activities. ME response to T3 in young rats was significantly greater than that found in aged rats regardless of diet. The age-related decrease in basal hepatic ME activity was not apparent in rats maintained on the high glucose or the high fructose diets, yet the T3 responsiveness of ME in rats maintained on these diets was not normalized. In adipose tissue, with the exception of the age-related changes in basal activity of the lipogenic enzymes, neither T3 nor the feeding of the test diets had any consistent effects. Since insulin resistance induced by high fructose feeding did not reduce hepatic lipogenic enzymes, it is unlikely that the age-related increase in insulin resistance explains the reduced lipogenic enzyme activity in aged rats. However, resistance to thyroid hormone action found in aged rats may partly account for the reduced hepatic lipogenic enzyme activity.

Aging↗
PubMed2002

Mechanical properties of visible light-cured resins reinforced with hydroxyapatite for dental restoration.

OBJECTIVES: The purpose of this study was to measure and analyze the mechanical properties of several composite materials designed for dental restoration. METHODS: The materials were composed of a visible light-curing monomer mixture (either Bis-GMA+TEGDMA or Bis-GMA+HEMA) as a matrix and hydroxyapatite (either microscopic or nanoscopic particles) as a reinforcing filler. The surface of the hydroxyapatite particles was modified by using a coupling agent (citric, malic, acrylic or methacrylic acid). Five specimens of 14 different composites were prepared for each mechanical test: flexural strength, Young's modulus and Vickers hardness. Mean values and standard deviations were calculated, and ANOVA and Student Newman Keuls multiple comparison tests were applied (P < 0.05). RESULTS: The addition of 50-60 wt% of hydroxyapatite particles to the unfilled monomer mixtures led to the increase of both Young's modulus and surface hardness of the material, while the flexural strength decreased. In general, when microscopic instead of nanoscopic hydroxyapatite was used as a reinforcing filler, mechanical properties were favored. The mechanical properties were also improved by adding citric, acrylic or methacrylic acid as a coupling agent. CONCLUSIONS: An adequate surface modification of the hydroxyapatite particles conferred enhanced mechanical properties to the final dental composite. Microscopic-hydroxyapatite particles are preferred to nanoscopic ones.

Acrylates↗
PubMed2004

Synthetic studies aimed at (-)-cochleamycin A. Evaluation of late-stage macrocyclization alternatives.

An efficient route to the fully functionalized ABC ring systems of the unnatural enantiomer of cochleamycin A was developed. L-(-)-Malic and L-(-)-ascorbic acids served well as starting materials for the two building blocks used to construct an (E,Z,E)-1,6,8-nonatriene intermediate. The AB part structure was assembled by way of a stereocontrolled intramolecular Diels-Alder cycloaddition via adoption of an endo transition state. From this vantage point, two general pathways were subsequently explored as to their suitability for elaboration of the CD rings. Initially examined was a protocol involving 10-membered carbocycle construction. When this approach was demonstrated not to be workable, attention was directed to 10-membered macrolactonization as an alternative tactic. Although assembly of the C-ring in this manner was easily achieved, ultimate closure of the six-membered ring to form ring D remains an unsolved problem.

Cyclopentanes↗
PubMed1999

(3R)-Chiral Control of 3-Alkyl-3-hydroxy-beta-lactams via Addition Reaction of Imines to Enolates of 1,3-Dioxolan-4-ones.

A method is described for the chiral construction of (3R)-3-alkyl-3-hydroxy-beta-lactams in a versatile and predictable manner. This protocol follows Seebach's synthetic principle of self-regeneration of stereocenters and has been applied to addition reactions among a selected number of imines and (2S)-chiral enolates of 1,3-dioxolan-4-ones. These reagents are easily available from the acetalization of (S)-alpha-hydroxy acids (lactic, mandelic, isovaleric, malic) and pivalaldehyde or pinacolone. In several cases, the addition of the enolate to the imine, the cyclization, and the removal of the auxiliary center occur in a one-step sequence, affording the corresponding beta-lactams as (3R,4S)-Z and (3R,4R)-E diastereomeric mixtures with high enantiomeric excesses. Four N-unsubstituted (3R,4S)-3-hydroxy-3-methyl-beta-lactams bearing 2-furyl (4e), phenylethenyl (4h), methoxycarbonyl (4i), and 2-thienyl (4l) substituents at C4 were obtained as major diastereomers and were purified by crystallization. The simultaneous presence of these substituents at C3 and C4 make these beta-lactams useful intermediates for the synthesis of new taxoids with interesting structural modifications at the isoserine moiety.

Journal Article↗
PubMed1988

Hormonal regulation of rat foetal lipogenesis in brown-adipocyte primary cultures.

Insulin stimulates lipogenesis by 100% for 5 h by a covalent modulation of acetyl-CoA carboxylase, and by 200% for 24 h by increasing malic enzyme and fatty acid synthase enzymic activities in brown-adipocyte primary cultures. At short times, noradrenaline and isoprenaline decrease lipogenesis. However, phenylephrine and glucagon have no effect. At long times, dexamethasone inhibits lipogenesis. This effect is precluded in the presence of insulin. Progesterone and tri-iodothyronine, alone or in the presence of insulin, produce a stimulation of the rates of lipogenesis.

Adipose Tissue, Brown↗
PubMed1999

Opposing actions of dehydroepiandrosterone and corticosterone in rats.

The purpose of this study was to determine the impact of dehydroepiandrosterone (DHEA) and corticosterone (CORT) treatment, using implants as a route of administration, on specific hormones, metabolites, and enzymes involved in energy metabolism. Sixty male Sprague-Dawley rats, 325 g initial weight, were implanted subcutaneously for 3 weeks with time-release pellets containing either DHEA or CORT at doses of 0, 10, 25, 50, or 100 mg in this 2 x 5 factorial experiment. In general, body weights and food intakes decreased as the level of steroid hormones increased. In contrast to DHEA treatment, rats receiving the 50- and 100-mg doses of CORT had lighter thymus glands and spleens and heavier epididymal and retroperitoneal fat pads than their controls. Rats treated with 100 mg of DHEA had lowered serum levels of triglycerides and lipid hydroperoxides whereas rats treated with 100 mg of CORT had higher levels of these blood lipids compared to their respective controls. In contrast to DHEA treatment, there was a dose-dependent increase in liver lipid content and the specific activities of the hepatic lipogenic enzymes glucose-6-phosphate dehydrogenase, malic enzyme, and fatty acid synthase in response to CORT treatment. Rats treated with 100 mg of DHEA had higher serum levels of IGF-1 than control rats. Conversely, rats treated with 100 mg of CORT had lower serum levels of IGF-1 and higher serum levels of testosterone, progesterone, and insulin than their controls. These data demonstrate the lipogenic actions of corticosterone in rats. Conversely, DHEA treatment reduced serum and hepatic lipids. Furthermore, these data suggest that using implants instead of bolus injections of steroids may be a more physiological approach for studying the influence of these steroids on lipid metabolism.

Animals↗
PubMed2001

Effects of photoperiod and feeding level on adipose tissue and muscle lipoprotein lipase activity and mRNA level in dry non-pregnant sheep.

The aim of the present study was to investigate the effects of photoperiod and feeding level on lipid metabolism in ovine perirenal and subcutaneous adipose tissues (AT) and in skeletal and cardiac muscles. Twenty dry non-pregnant ovariectomised ewes were divided into two groups and subjected to either 8 h or 16 h light/d, and underfed at 22 % energy requirements for 7 d. Half of the ewes in each group were slaughtered and the remaining ewes were refed at 190 % energy requirements for 14 d, until slaughtering. Refeeding increased (2.6-4.3-fold) malic enzyme (ME), fatty acid synthase (FAS), glucose-6-phosphate dehydrogenase (G6PDH) and glycerol-3-phosphate dehydrogenase (G3PDH) activities in subcutaneous AT as well as lipoprotein lipase (LPL) activity in perirenal (3.5-fold) and subcutaneous (10-fold) AT and to a lesser extent (1.4-fold) in the skeletal longissimus thoracis and cardiac muscles. Moreover, variations of LPL mRNA level followed variations of LPL activity: refeeding increased perirenal AT- and cardiac muscle-mRNA levels (7.4- and 2-fold respectively). The main finding of this study is that, for a given level of food intake, long days (compared with short days) increased the LPL activity in the longissimus thoracis muscle and, in refed ewes, the activities of LPL and ME in subcutaneous AT. Furthermore, long days increased LPL mRNA level in cardiac muscle and perirenal AT. Thus, our results show that there are direct effects of photoperiod on sheep AT lipogenic potential, as well as on muscle LPL activity, which are not caused by changes in nutrient availability.

Adipose Tissue↗