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Query: EC:2.3.1.21 (
CPT
)
4,580
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Much biochemical evidence has implicated rat adipocyte
CD36
(FAT) in membrane binding and transport of long-chain fatty acids (FA). Expression of the mRNA favored tissues with active FA metabolism and was upregulated in vivo with diabetes and with high fat feeding. In culture,
CD36
mRNA was a strong marker of preadipocyte differentiation and was modulated by the same factors effective on mRNAs coding for other proteins involved in FA metabolism. In preadipocytes, long-chain FA or 2-bromopalmitate but not short-chain FA strongly induced
CD36
mRNA within 8 h to an optimum within 24 h. Removal of the FA resulted in a decay of
CD36
mRNA with a half life of about 12 h. In differentiated adipocytes, levels of
CD36
mRNA were downregulated by the 3': 5'-cyclic adenosine monophosphate, cAMP, analog, 8-(4-chlorophenylthio) adenosine, 8-
CPT
, at concentrations of 1-100 microM. The effect, observed within 6 h, was optimal after 18 h and independent of the action of 8-
CPT
to mobilize FA. Regulation of
CD36
expression by factors effective on expression of other proteins implicated in FA metabolism is consistent with its role in membrane FA transport.
...
PMID:Regulation of FAT/CD36 gene expression: further evidence in support of a role of the protein in fatty acid binding/transport. 925 Jun 3
The effect of peroxisome proliferator-activated receptor (PPAR)-alpha activators on the liver is well established, but the other effects on muscle and adipose tissue about lipid metabolism and insulin sensitivity are not clear. We investigated whether PPAR-alpha activation affects adiposity of skeletal muscle as well as adipose tissue and improves insulin sensitivity in spontaneous type 2 diabetes model, Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Thirty-three weeks of aged, 20 male OLETF rats were divided into two groups. Control group (n=10) was fed with chow and treatment group (n=10) with chow contained fenofibrate for 7 weeks. At the age of 40 weeks, all rats were examined with MRI, intravenous glucose tolerance test, and then sacrificed for measurement of fat mass and RNA analyses. The total fat (the sum of subcutaneous, mesenteric, epididymal, and retroperitoneal fat pads) measured by dissection was significantly reduced in treatment group. The signal intensity of muscular adiposity was significantly decreased in treatment group. The mRNA levels of FAT/
CD36
and mitochondrial
carnitine palmitoyltransferase I
(M-CPT I) in liver were remarkably increased. Fasting plasma insulin and leptin levels, insulin response after intravenous glucose loading and homeostasis model assessment insulin resistance (HOMA(IR)) index were lowered in treatment group. Fenofibrate increase mitochondrial fatty acid beta-oxidation in liver but not in skeletal muscle and lower the plasma levels of triglyceride and free fatty acid. It might result in reduction of adiposity of truncal adipose tissue and skeletal muscle. We suggest that reduction of adiposity in trunk and skeletal muscle might improve insulin sensitivity.
...
PMID:Fenofibrate lowers abdominal and skeletal adiposity and improves insulin sensitivity in OLETF rats. 1216 16
The adipocyte-derived cytokine, resistin, has been proposed as the link between obesity and type 2 diabetes mellitus in murine models. In humans, resistin is identical to FIZZ3 (found in inflammatory zone 3), which belongs to a family of proteins that appears to be involved in inflammatory processes. To study the mechanisms by which fibrates improve glucose homeostasis, we determined resistin mRNA levels by using relative quantitative reverse-transcriptase-polymerase chain reaction (RT-PCR) in omental white adipose tissue samples obtained from patients treated with placebo or fenofibrate (200 mg/d) for 8 weeks before elective cholecystectomy. Fenofibrate treatment reduced total plasma cholesterol and low-density lipoprotein (LDL)-cholesterol levels by 24% and 35%, respectively. Compared with placebo values, a 2.4-fold induction in resistin mRNA levels was observed in white adipose tissue of fenofibrate-treated patients, whereas no changes were observed in the mRNA levels of the well-known perosixome proliferator-activated receptor (PPAR) target genes
CD36
, acyl-CoA oxidase, and
carnitine palmitoyltransferase
. These findings indicate that resistin changes were not related to PPAR activation by fenofibrate. Interestingly, resistin mRNA levels showed a negative correlation with plasma cholesterol levels (r2 =.53, P =.039, n = 8), but not with triglyceride levels (r2 =.02, P =.73, n = 8). These results suggest that cholesterol regulates resistin expression in human white adipose tissue.
...
PMID:Reductions in plasma cholesterol levels after fenofibrate treatment are negatively correlated with resistin expression in human adipose tissue. 1264 75
Peroxisome proliferator-activated receptors (PPARs) are key regulators of macrophage lipid metabolism. We compared the effects of three PPAR activators (bezafibrate, fenofibrate, and troglitazone) on the mRNA levels of genes involved in lipid metabolism in primary human macrophages and macrophage-derived foam cells. Treatment of human macrophages for 24 hours with 100 micro mol/L bezafibrate, a nonselective drug that activates the 3 PPAR subtypes (PPARalpha, PPARbeta/delta, and PPARgamma), caused an 87% (P <.01) and a 230% rise in
CD36
and adipocyte fatty acid-binding protein (aP2) mRNA levels, respectively, whereas the expressions of PPARgamma, PPARalpha, acyl-CoA oxidase,
carnitine palmitoyltransferase I
(CPT-I), adenosine triphosphate (ATP)-binding cassette transporter 1 (ABCA1), neutral cholesteryl ester hydrolase, and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) were not modified. However, treatment with selective PPARalpha (fenofibrate at 100 micro mol/L) and PPARgamma (troglitazone at 5 micro mol/L) activators had different effects. Fenofibrate increased PPARalpha (62%, P <.05) and LOX-1 (180%, P <.05) mRNA levels; and troglitazone upregulated
CPT
-I expression (75%, P <.05). When the effects of these drugs were assessed in macrophage-derived foam cells, we found that troglitazone caused a 134% (P <.05) and a 66% (P <.01) rise in ABCA1 and
CPT
-I mRNA levels, respectively, whereas the 3 drugs significantly increased aP2 transcripts (about 100% induction). Given that troglitazone treatment resulted in the upregulation of genes involved in the mitochondrial beta-oxidation of fatty acids (CPT-I) and in the reverse-cholesterol-transport pathway (ABCA1), we subsequently determined whether these changes affected intracellular cholesterol ester accumulation. In macrophage-derived foam cells a significant reduction (32%, P <.01) was observed in intracellular cholesterol accumulation after troglitazone, but not after bezafibrate or fenofibrate treatment. Since
CPT
-I inhibition promotes cholesterol incorporation into cholesteryl esters in macrophages, study is now needed on whether
CPT
-I induction by troglitazone may reduce the availability of fatty acids for synthesizing cholesterol esters, leading to less foam cell formation.
...
PMID:Differential effects of peroxisome proliferator-activated receptor activators on the mRNA levels of genes involved in lipid metabolism in primary human monocyte-derived macrophages. 1275
Peroxisome proliferator-activated receptor-alpha (PPARalpha) is a key regulator of fatty acid oxidation in skeletal muscle, but few data exist from humans in vivo. To investigate whether insulin sensitivity in skeletal muscle and body mass index (BMI) were associated with skeletal muscle expression of PPARalpha and with important genes regulating lipid metabolism in humans in vivo, we undertook hyperinsulinemic-euglycemic clamps and measured PPARalpha mRNA levels and mRNA levels of lipid regulating PPARalpha response genes in skeletal muscle biopsies. mRNA levels were measured in 16 men, using a novel highly sensitive and specific medium throughput quantitative competitive PCR that allows reproducible measurement of multiple candidate mRNAs simultaneously. mRNA levels of PPARalpha were positively correlated with mRNA levels of
CD36
(r = 0.77, P = 0.001), lipoprotein lipase (r = 0.54, P = 0.024), muscle-type
carnitine palmitoyltransferase
-I (r = 0.54, P = 0.024), uncoupling protein-2 (r = 0.63, P = 0.008), and uncoupling protein-3 (r = 0.53, P = 0.026), but not with measures of insulin sensitivity, BMI, or GLUT4, which plays an important role in insulin-mediated glucose uptake. Thus our data suggest that in humans skeletal muscle PPARalpha expression and genes regulating lipid metabolism are tightly linked, but there was no association between both insulin sensitivity and BMI with PPARalpha expression in skeletal muscle.
...
PMID:Human skeletal muscle PPARalpha expression correlates with fat metabolism gene expression but not BMI or insulin sensitivity. 1451 97
Hypertension-induced pathological cardiac hypertrophy (hypertensive heart) and exercise training-induced physiological cardiac hypertrophy (athletic heart) have differences in cardiac properties. We hypothesized that gene expression of energy metabolic enzymes differs between these two types of cardiac hypertrophy. To investigate whether mRNA expression of key enzymes in the long-chain fatty acid (FA), glucose, and lactic acid metabolic pathways differs between these two types of cardiac hypertrophy, we used the hearts of spontaneously hypertensive rats (SHR; 19 weeks old) as a model of the hypertensive heart, swim-trained rats (Trained; 19 weeks old, swimming training for 15 weeks) as a model of the athletic heart, and sedentary Wistar-Kyoto rats (Control; 19 weeks old). SHR developed hypertensive cardiac hypertrophy, of which cardiac function was deteriorated, whereas Trained rats developed an athletic heart, of which cardiac function was enhanced. The mRNA expression of
CD36
, which involved in uptake of long-chain FA, in the heart was almost never detected in the SHR group. Furthermore, the mRNA expression of key enzymes in the long-chain FA metabolic pathway (acyl CoA synthase [ACoAS], carnitine palmitoyl transferase [
CPT
]-I,
CPT
-II, and isocitrate dehydrogenase [ISCD]) in the heart was significantly higher in the SHR group compared with the Control group. The mRNA expression of ACoAS,
CPT
-I, ISCD, and
CD36
in the heart did not differ between Trained group and Control group, whereas that of
CPT
-II in the Trained group was significantly higher compared with the Control group. The mRNA expression of key enzymes (phosphofructokinase and lactate dehydrogenase) in glycolytic metabolic pathway in the heart was markedly higher in the SHR group compared with the Control group, whereas these mRNA expressions did not differ between Trained group and Control group. These findings suggest that the molecular phenotypes in the energy metabolic system differ in hypertension-induced pathological and exercise training-induced physiological cardiac hypertrophy, and these differences may participate in the differences in cardiac function.
...
PMID:Cardiac hypertrophy by hypertension and exercise training exhibits different gene expression of enzymes in energy metabolism. 1462 Nov 87
Severe sepsis results in the decreased uptake and oxidation of fatty acids in the heart and cardiac failure. Some of the key proteins required for fatty acid uptake and oxidation in the heart have been shown to be downregulated after endotoxin (LPS) administration. The nuclear hormone receptors, peroxisome proliferator-activated receptor (PPAR) and thyroid receptor (TR), which heterodimerize with the retinoid X receptor (RXR), are important regulators of fatty acid metabolism and decrease in the liver after LPS administration. In the present study, we demonstrate that LPS treatment produces a rapid and marked decrease in the mRNA levels of all three RXR isoforms, PPARalpha and PPARdelta, and TRalpha and TRbeta in the heart. Moreover, LPS administration also decreased the expression of the coactivators CREB-binding protein (CBP)/p300, steroid receptor coactivator (SRC)-1, SRC-3, TR-associated protein (TRAP)220, and PPARgamma coactivator (PGC)-1, all of which are required for the transcriptional activity of RXR-PPAR and RXR-TR. In addition, the mRNA levels of the target genes malic enzyme, Spot 14, sarcoplasmic reticulum Ca2+-ATPase, or SERCA2, the VLDL receptor, fatty acyl-CoA synthetase, fatty acid transporter/
CD36
,
carnitine palmitoyltransferase
Ibeta, and lipoprotein lipase decrease in the heart after LPS treatment. The decrease in expression of RXRalpha, -beta, and -gamma, PPARalpha and -delta, and TRalpha and -beta, and of the coactivators CBP/p300, SRC-1, SRC-3, TRAP220, and PGC-1 and the genes they regulate, induced by LPS in the heart, could account for the decreased expression of key proteins required for fatty acid oxidation and thereby play an important role in cardiac contractility. These alterations could contribute to the myocardial dysfunction that occurs during sepsis.
...
PMID:Altered expression of nuclear hormone receptors and coactivators in mouse heart during the acute-phase response. 1470 65
Changes in dietary macronutrient intake alter muscle and blood substrate availability and are important for regulating gene expression. However, few studies have examined the effects of diet manipulation on gene expression in human skeletal muscle. The aim of this study was to quantify the extent to which altering substrate availability impacts on subsequent mRNA abundance of a subset of carbohydrate (CHO)- and fat-related genes. Seven subjects consumed either a low- (LOW; 0.7 g/kg body mass CHO) or high- (HIGH; 10 g/kg body mass CHO) CHO diet for 48 h after performing an exhaustive exercise bout to deplete muscle glycogen stores. After intervention, resting muscle and blood samples were taken. Muscle was analyzed for the gene abundances of GLUT4, glycogenin, pyruvate dehydrogenase kinase-4 (PDK-4), fatty acid translocase (FAT/
CD36
),
carnitine palmitoyltransferase I
(CPT I), hormone-sensitive lipase (HSL), beta-hydroxyacyl-CoA dehydrogenase (beta-HAD), and uncoupling binding protein-3 (UCP3), and blood samples for glucose, insulin, and free fatty acid (FFA) concentrations. Glycogen-depleting exercise and HIGH-CHO resulted in a 300% increase in muscle glycogen content (P < 0.001) relative to the LOW-CHO condition. FFA concentrations were twofold higher after LOW- vs. HIGH-CHO (P < 0.05). The exercise-diet manipulation exerted a significant effect on transcription of all carbohydrate-related genes, with an increase in GLUT4 and glycogenin mRNA abundance and a reduction in PDK-4 transcription after HIGH-CHO (all P < 0.05). FAT/
CD36
(P < 0.05) and UCP3 (P < 0.01) gene transcriptions were increased following LOW-CHO. We conclude that 1) there was a rapid capacity for a short-term exercise and diet intervention to exert coordinated changes in the mRNA transcription of metabolic related genes, and 2) genes involved in glucose regulation are increased following a high-carbohydrate diet.
...
PMID:Regulation of metabolic genes in human skeletal muscle by short-term exercise and diet manipulation. 1476 78
Fatty acid translocase (FAT)/
CD36
is a long chain fatty acid transporter present at the plasma membrane, as well as in intracellular pools of skeletal muscle. In this study, we assessed the unexpected presence of FAT/
CD36
in both subsarcolemmal and intermyofibril fractions of highly purified mitochondria. Functional assessments demonstrated that the mitochondria could bind (14)C-labeled palmitate, but could only oxidize it in the presence of carnitine. However, the addition of sulfo-N-succinimidyl oleate, a known inhibitor of FAT/
CD36
, resulted in an 87 and 85% reduction of palmitate oxidation in subsarcolemmal and intermyofibril fractions, respectively. Further studies revealed that maximal
carnitine palmitoyltransferase I
(
CPTI
) activity in vitro was inhibited by succinimidyl oleate (42 and 48% reduction). Interestingly,
CPTI
immunoprecipitated with FAT/
CD36
, indicating a physical pairing. Tissue differences in mitochondrial FAT/
CD36
protein follow the same pattern as the capacity for fatty acid oxidation (heart >> red muscle > white muscle). Additionally, chronic stimulation of hindlimb muscles (7 days) increased FAT/
CD36
expression and also resulted in a concomitant increase in mitochondrial FAT/
CD36
content (46 and 47% increase). Interestingly, with acute electrical stimulation of hindlimb muscles (30 min), FAT/
CD36
expression was not altered, but there was an increase in the mitochondrial content of FAT/
CD36
compared with the non-stimulated control limb (35 and 37% increase). Together, these data suggest a role for FAT/
CD36
in mitochondrial long chain fatty acid uptake and demonstrate system flexibility to match FAT/
CD36
mitochondrial content with an increased capacity for fatty acid oxidation, possibly involving translocation of FAT/
CD36
to the mitochondria.
...
PMID:A novel function for fatty acid translocase (FAT)/CD36: involvement in long chain fatty acid transfer into the mitochondria. 1516 24
Whether a high-unsaturated-fat, high-protein (HFP), and low-carbohydrate (CHO) diet during gestation has long-lasting beneficial effects on lipid metabolism in the offspring was investigated using a mouse model. Female mice were fed either a standard (CHO rich) chow diet or a CHO HFP diet, before and during gestation and lactation. All offspring were weaned onto the same chow until adulthood. Although liver cholesterol concentration and fasting plasma triglyceride (TG), cholesterol, and free fatty acid concentrations were not affected in either male or female HFP offspring, hepatic TG concentration was reduced by approximately 51% (P < 0.05) in the female adult offspring from dams on the HFP diet, compared with females from dams on the chow diet (a trend toward reduced TG concentration was also observed in the male). Furthermore, hepatic protein levels for
CD36
,
carnitine palmitoyltransferase
-1 (CPT-1), and peroxisomal proliferator activated receptor-alpha (PPAR-alpha) were increased by approximately 46% (P < 0.001), approximately 52% (P < 0.001), and approximately 14% (P = 0.035), respectively, in the female HFP offspring. Liver TG levels were negatively correlated with protein levels of CD 36 (r = -0.69, P = 0.007),
CPT
-1 (r = -0.55, P = 0.033), and PPAR-alpha (r = -0.57, P = 0.025) in these offspring. In conclusion, a maternal HFP diet during gestation and lactation reduces hepatic TG concentration in female offspring, which is linked with increased protein levels in fatty acid oxidation.
...
PMID:High-unsaturated-fat, high-protein, and low-carbohydrate diet during pregnancy and lactation modulates hepatic lipid metabolism in female adult offspring. 1531 18
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