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1.
J Physiol Biochem ; 59(2): 101-10, 2003 Jun.
Article in English | MEDLINE | ID: mdl-14649875

ABSTRACT

For a better understanding of the hyperlipidemic function of saturated fat, we have studied the effects of diet supplementation with 10-20% coconut oil on the chick plasma and lipoprotein composition under postprandial and starvation conditions. A significant hypercholesterolemia was found in chicks fed the standard diet after 12 h of food deprivation. In these conditions, LDL-cholesterol also increased, whereas triglyceride levels were reduced in HDL, VLDL and chylomicron fractions. Coconut oil induced a significant hypercholesterolemia under both conditions, also increasing the plasma triglyceride content under postprandial conditions, but not after starvation. Coconut oil feeding increased all the chemical components of HDL, especially under postprandial conditions, but did not affect the HDL-triglycerides under food-deprivation conditions. Total cholesterol and triglyceride levels in LDL increased after coconut oil supplementation to the diet. Differences were more pronounced under postprandial conditions. Changes in VLDL and chylomicron composition were less evident.


Subject(s)
Cholesterol/blood , Fasting/physiology , Plant Oils/pharmacology , Animals , Chickens , Cholesterol, HDL/blood , Cholesterol, LDL/blood , Cholesterol, VLDL/blood , Coconut Oil , Dietary Fats/blood , Hypercholesterolemia/blood , Male , Postprandial Period
2.
Comp Biochem Physiol B Biochem Mol Biol ; 133(2): 269-75, 2002 Oct.
Article in English | MEDLINE | ID: mdl-12381389

ABSTRACT

For a better understanding of the hyperlipidemic function of saturated fat, we have studied the comparative effects of diet supplementation with 10 and 20% coconut oil on the main lipid classes of chick plasma. Changes in fatty acid composition of free fatty acid and triglyceride fractions were parallel to that of the experimental diet. Thus, the increase in the percentages of 12:0 and 14:0 acids may contribute to the hypercholesterolemic effects of coconut oil feeding. Plasma phospholipids incorporated low levels of 12:0 and 14:0 acids whereas 18:0, the main saturated fatty acid of this fraction, also increased after coconut oil feeding. The percentage of 20:4 n-6 was higher in plasma phospholipids than in the other fractions and was significantly decreased by our dietary manipulations. Likewise, minor increases were found in the percentages of 12:0 and 14:0 acids in plasma cholesterol esters. However, the percentage of 18:2 acid significantly increased after coconut oil feeding. Our results show a relationship between fatty acid composition of diets and those of plasma free fatty acid and triglyceride fractions, whereas phospholipids and cholesterol esters are less sensitive to dietary changes.


Subject(s)
Chickens/blood , Fatty Acids/chemistry , Lipids/chemistry , Plant Oils , Animals , Cholesterol Esters/blood , Cholesterol Esters/chemistry , Coconut Oil , Dietary Supplements , Fatty Acids/blood , Growth , Lipids/blood , Male , Phospholipids/blood , Phospholipids/chemistry , Triglycerides/blood , Triglycerides/chemistry
3.
J Physiol Biochem ; 58(1): 33-41, 2002 Mar.
Article in English | MEDLINE | ID: mdl-12222745

ABSTRACT

The comparative effects of 10-20% coconut oil feeding on fatty acid composition of the main lipid classes of chick plasma have been studied with and without simultaneous treatment with dipyridamole in order to clarify the hypolipidemic role of this drug. Coconut oil drastically increased the percentages of lauric and myristic acids in free fatty acid and triacylglycerol fractions, whereas these changes were less pronounced in phospholipids and cholesterol esters. The percentage of arachidonic acid was higher in plasma phospholipids than in the other fractions and was significantly decreased by coconut oil feeding. Linoleic acid, the main fatty acid of cholesterol esters, was drastically increased by coconut oil feeding. Changes induced by the simultaneous administration of dipyridamole were more pronounced in the phospholipids and cholesterol esters than in the other fractions. The fall observed in linoleic acid levels after dipyridamole treatment may be of interest for a lower production of its derived eicosanoids, especially in plasma phospholipids and cholesterol esters.


Subject(s)
Chickens/blood , Dipyridamole/pharmacology , Lipids/blood , Plant Oils/pharmacology , Animals , Coconut Oil , Dietary Fats/administration & dosage , Dietary Fats/pharmacology , Hypercholesterolemia/blood , Hypercholesterolemia/chemically induced , Male
4.
J Nutr Biochem ; 10(6): 325-30, 1999 Jun.
Article in English | MEDLINE | ID: mdl-15539306

ABSTRACT

We studied the short-term effects of a 20% coconut oil supplementation to the chick diet on lipid composition of liver and hepatic mitochondria, and changes that occurred in mitochondrial-associated enzymes as a result of this diet. No significant differences were observed in the lipid contents of liver when young chicks were fed the experimental diet, whereas hepatic mitochondria rapidly changed in response to this diet. Total cholesterol significantly increased in mitochondria at 24 hours of coconut oil diet feeding and decreased when dietary treatment was prolonged for 5 to 14 days. Changes in total mitochondrial phospholipids showed an inverse profile. A significant decrease in phosphatidylethanolamine and an increase in sphingomyelin were found at 24 hours. The cholesterol/phospholipid molar ratio significantly and rapidly (24 hours) increased in mitochondria from treated animals. Cytochrome oxidase activity drastically increased after 24 hours of experimental diet feeding and lowered to the control values when dietary manipulation was prolonged for 5 to 14 days. ATPase activity showed an inverse profile. Changes in cytochrome oxidase activity were parallel to changes in the cholesterol/phospholipid molar ratio, whereas changes in ATPase activity showed an inverse correlation with changes in this molar ratio. To our knowledge, this is one of the first reports on the very rapid response (24 hours) of mitochondrial lipid composition and function to saturated fat feeding.

5.
Article in English | MEDLINE | ID: mdl-9297804

ABSTRACT

Supplementation of 20% coconut oil from two commercial sources pharmaceutical ("Pharmacy") and cooking ("Pastry") use, to the chick diet for 14 days produced a clear damage to the hepatic mitochondria, accompanied by an accumulation of glycogen and lipid droplets in the hepatocyte cytoplasm. These effects may be accounted for the high proportion of fat supplemented to the diets (20%). Pharmacy coconut oil induced a high percentage of cellular death when administered for 14 days. Fatty acid profiles in liver and hepatic mitochondria rapidly changed (24 hr) after both coconut oils supplementation to the diet. The accumulation of shorter chain fatty acids (12:0 and 14:0) was always higher after Pharmacy than after Pastry diet feeding. This fact may contribute, at least in part, to the cellular damage mentioned above especially after Pharmacy diet feeding. Mitochondrial ratios of saturated/unsaturated and saturated/polyunsaturated fatty acids rapidly changed in parallel to these ratios in both diets. Most of the mitochondrial parameters measured tend to recuperate the control values when diets were supplied for 5-14 days. Nevertheless, the maintenance of the mentioned ratios after 14-days Pharmacy diet feeding at significantly higher levels than those observed in control, seems to suggest the lack of the homeostatic mechanism in these membranes and could be also related with the high percentage of cellular death observed after this dietary manipulation.


Subject(s)
Fatty Acids/analysis , Liver/drug effects , Mitochondria, Liver/drug effects , Plant Oils/toxicity , Animals , Cell Death/drug effects , Chickens , Coconut Oil , Cytoplasm/metabolism , Diet , Glycogen/metabolism , Lipid Metabolism , Liver/metabolism , Liver/ultrastructure , Male , Microscopy, Electron , Mitochondria, Liver/metabolism , Mitochondria, Liver/ultrastructure , Plant Oils/administration & dosage , Plant Oils/analysis , Time Factors
6.
Biochimie ; 79(6): 333-40, 1997 Jun.
Article in English | MEDLINE | ID: mdl-9310182

ABSTRACT

Supplementation of coconut oil to the diet for 1-2 weeks produced a significant hypercholesterolemia in 14-day-old chicks. Changes in plasma fatty acid composition correlated positively with those of diets. In this study, we have shown a different response of low- and high-density lipoprotein (LDL and HDL) fractions to dietary saturated fat (coconut oil) rich in lauric and myristic acids. Although all the components of these particles seemed to increase, the percentages of increases found in total (TC), free (FC) and esterified cholesterol (EC) were higher in LDL than in HDL. TC/phospholipid (PL) ratio, considered as an inverse index of membrane fluidity, also increased with the dietary regimen in LDL, while no significant differences were found in HDL. These results suggest that supplementation of coconut oil to the diet decreased the fluidity of LDL. The EC/triglycerides (TG) ratio was also significantly increased in LDL, corroborating the main atherogenic function of this lipoprotein fraction in response to lauric and myristic acids. We have also estimated the lipidic order parameter, S, from the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH)-labelled low- and high-density lipoproteins. In LDL, temperature dependence of S shows two different behaviour zones at about 20 degrees C. In HDL, the plot of S values versus T is linear. DPH anisotropy and S increased in both LDL and HDL from treated chicks. This increase becomes more evident as temperature rises and also with dietary treatment.


Subject(s)
Cocos , Dietary Fats/administration & dosage , Lipoproteins, HDL/biosynthesis , Lipoproteins, HDL/chemistry , Lipoproteins, LDL/biosynthesis , Lipoproteins, LDL/chemistry , Plant Oils/administration & dosage , Animals , Anisotropy , Chemical Phenomena , Chemistry, Physical , Chickens , Coconut Oil , Lipoproteins/blood , Lipoproteins/chemistry , Lipoproteins, HDL/blood , Lipoproteins, LDL/blood , Male , Plasma/chemistry , Temperature
7.
J Biochem ; 119(4): 610-6, 1996 Apr.
Article in English | MEDLINE | ID: mdl-8743559

ABSTRACT

Supplementation of 10 or 20% coconut oil in the diet for 1-2 weeks produced a significant hypercholesterolemia in neonatal chicks. Plasma triacylglycerol concentration significantly increased after the addition of 20% coconut oil for 2 weeks. These results show that newborn chicks are more sensitive to saturated fatty acids from coconut oil than adult animals. The effects of this saturated fat on lipoprotein composition were studied for the first 1-2 weeks of neonatal chick life. Coconut oil supplementation in the diet (20%) for 2 weeks increased cholesterol concentration in all the lipoprotein fractions, while 10% coconut oil only increased cholesterol in low-density and very-low-density lipoproteins, an increase that was significant after 1 week of treatment. Similar results were obtained for triacylglycerol concentration after 2 weeks of treatment. Changes in phospholipid and total protein levels were less profound. Coconut oil decreased low-density and very-low-density lipoprotein fluidity, measured as total cholesterol/phospholipid ratio. Changes in esterified cholesterol/phospholipid and triacylglycerol/phospholipid ratios suggest that coconut oil affects the distribution of lipid components in the core of very-low-density particles. Likewise, the esterified cholesterol/triacylglycerol ratio was clearly increased in the low-density, and especially in the very-low-density, fraction after the first week of coconut oil feeding. Our results show that neonatal chick provides a suitable model in which to study the role of very-low-density lipoproteins in atherogenesis and the rapid response to saturated fatty acids with 12-14 carbons.


Subject(s)
Cocos , Dietary Fats, Unsaturated/adverse effects , Hypercholesterolemia/etiology , Lipoproteins/blood , Plant Oils/adverse effects , Age Factors , Animals , Animals, Newborn , Chickens , Cholesterol/analysis , Cholesterol/blood , Coconut Oil , Diet , Fatty Acids/analysis , Hypercholesterolemia/blood , Lipids/analysis , Lipids/blood , Lipoproteins/chemistry , Male , Molecular Weight , Triglycerides/analysis , Triglycerides/blood
8.
Comp Biochem Physiol Comp Physiol ; 106(4): 799-802, 1993 Dec.
Article in English | MEDLINE | ID: mdl-7906638

ABSTRACT

1. The composition of HDL, the major lipoprotein fraction from chick serum, drastically changed after 2 weeks of coconut oil feeding. Total cholesterol and triacylglycerols significantly increased following dietary 10 or 20% coconut oil supplementation. 2. Changes in LDL composition were less profound, cholesterol being the only component that increased by coconut oil supplementation (10 or 20%). 3. IDL proteins were the only components that increased following the same dietary treatment (20%). 4. VLDL cholesterol and proteins also increased after 1-2 weeks of 20% coconut oil supplementation to the diet. 5. Of total lipoproteins, the cholesterol content strongly increased after dietary treatment, while triacylglycerols did not change significantly.


Subject(s)
Dietary Fats/pharmacology , Lipoproteins/blood , Plant Oils/pharmacology , Animals , Apoproteins/blood , Chickens , Cholesterol/blood , Coconut Oil , Fatty Acids/pharmacology , Lipoproteins, HDL/blood , Lipoproteins, LDL/blood , Lipoproteins, VLDL/blood , Male , Triglycerides/blood
9.
Lipids ; 28(10): 913-6, 1993 Oct.
Article in English | MEDLINE | ID: mdl-8246691

ABSTRACT

The effect of dietary lipid levels on the levels of cholesterol and the activities of the major cholesterogenic enzymes of the liver has been studied in the European eel. An increase in hepatic total cholesterol was observed when the dietary lipid levels increased from 12 to 20%, while protein levels were maintained at 30%. This change paralleled an increase in mevalonate 5-pyrophosphate decarboxylase activity, while 3-hydroxy-3-methylglutaryl-CoA reductase mevalonate kinase and mevalonate 5-phosphate kinase were not affected by changes in diet composition. These results suggest that the decarboxylase may be a rate-limiting enzyme in cholesterogenesis in eel liver.


Subject(s)
Cholesterol/metabolism , Dietary Fats/pharmacology , Liver/metabolism , Anguilla , Animals , Carboxy-Lyases/metabolism , Fatty Acids/analysis , Hydroxymethylglutaryl CoA Reductases/metabolism , Liver/drug effects , Liver/enzymology , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Phosphotransferases (Phosphate Group Acceptor)/metabolism
10.
Article in English | MEDLINE | ID: mdl-7684279

ABSTRACT

The effect of protein/lipid ratio of diets on hepatic cholesterol has been studied in European eel and correlated with changes in the main enzymes responsible for cholesterol metabolism. The growth rates of animals were similar when dietary lipid level was 12%. However, a 25% protein/20% fat (25/20) diet produced a decrease in the weight gain when compared with that observed after feeding a 30/20 diet. At low fat level (12%), the decrease in dietary protein produced a little but significant increase in total cholesterol, mainly due to the esterified form. On the contrary, a 25/20 diet produced a lower cholesterol accumulation than that a 30/20 diet. These results suggest that a minimal protein level was required for an optimal utilization of dietary fat for cholesterol deposition in liver. No significant differences were found in 3-hydroxy-3-methylglutaryl-CoA reductase, mevalonate kinase, mevalonate 5-phosphate kinase and mevalonate 5-pyrophosphate decarboxylase when compared the effect of 40/12 and 30/12 diets as well as that of 30/20 and 25/20 diets, suggesting that differences in hepatic cholesterol content were not due to differences in cholesterol synthesis but in the transport to the liver. Changes in the esterified cholesterol were parallel to those found in acyl-CoA: cholesterol acyltransferase, corroborating the main role of this enzyme in the regulation of hepatic cholesterol esterification.


Subject(s)
Cholesterol/biosynthesis , Dietary Fats/administration & dosage , Dietary Proteins/administration & dosage , Lipids/administration & dosage , Liver/metabolism , Acyl Coenzyme A/metabolism , Anguilla , Animals , Body Weight/physiology , Esterification , Liver/enzymology
11.
Arch Int Physiol Biochim Biophys ; 100(2): 133-6, 1992.
Article in English | MEDLINE | ID: mdl-1379489

ABSTRACT

The effect of coconut oil supplementation to the diet (10 or 20%) on lipid levels in plasma and liver as well as on the cholesterogenic enzyme activity were studied in 14-day-old chicks. Treatments for 1 or 2 weeks did not interfere in the growth rate of animals nor in the liver weight. The 10% coconut oil group showed a significant increase of plasma cholesterol after 2 weeks of treatment, while after 1 week the increase was not statistically significant. The 20% coconut oil group increased plasma cholesterol from the first week. Triacylglycerol content increased after each coconut oil supplementation to the diet during the first week. Hepatic cholesterol did not change significantly after any treatment assayed. No significant difference was observed in the cholesterogenic activity, measured as hepatic 3-hydroxy-3-methylglutaryl-CoA reductase, so that this study provides a perfect model of hypercholesterolemic animals without changes in their cholesterogenic ability.


Subject(s)
Dietary Fats , Hydroxymethylglutaryl CoA Reductases/metabolism , Hypercholesterolemia/chemically induced , Liver/enzymology , Plant Oils/administration & dosage , Animals , Chickens , Cholesterol/blood , Cholesterol/metabolism , Coconut Oil , Liver/metabolism , Triglycerides/blood , Triglycerides/metabolism
12.
Arch Int Physiol Biochim Biophys ; 100(1): 19-22, 1992.
Article in English | MEDLINE | ID: mdl-1380327

ABSTRACT

Serum lipoproteins from 12h fasted male chicks (15-day-old) were separated into 20 fractions by isopycnic density gradient ultracentrifugation. A new procedure was described by collecting the different fractions from the bottom of tube instead of by aspiration from the meniscus of each tube. Analyses of chemical composition of serum lipoproteins have permitted to reevaluate the density limits of major classes: VHDL, d greater than 1.132 g/ml; HDL, d 1.132-1.084 g/ml; LDL, d 1.084-1.038; IDL, d 1.038-1.022; and VLDL d less than 1.022. HDL fractions clearly predominated (approx. 77% of total lipoproteins) while IDL and VLDL were present at low percentage. LDL was the fraction richest in cholesterol; triacylglycerol content clearly increased from HDL to VLDL, while protein content decreased. All the chemical components of chick serum lipoproteins were accumulated in HDL, although triacylglycerol was relatively distributed in all the lipoprotein classes.


Subject(s)
Lipoproteins/chemistry , Animals , Blood Proteins/metabolism , Centrifugation, Density Gradient/methods , Chickens , Cholesterol/blood , Lipoproteins/blood , Lipoproteins/isolation & purification , Male , Phospholipids/blood , Triglycerides/blood , Ultracentrifugation
13.
Mol Cell Biochem ; 105(1): 21-5, 1991 Jun 26.
Article in English | MEDLINE | ID: mdl-1922006

ABSTRACT

Phenylalanine, phenylpyruvate and phenylacetate produced a considerable inhibition of chick liver mevalonate 5-pyrophosphate decarboxylase while mevalonate kinase and mevalonate 5-phosphate kinase were not significantly affected. Phenolic derivatives of phenylalanine produced a similar inhibition of decarboxylase activity than that found in the presence of phenyl metabolites. The degree of inhibition was progressive with increasing concentrations of inhibitors (1.25-5.00 mM). Simultaneous supplementation of different metabolites in conditions similar to those in experimental phenylketonuria (0.25 mM each) produced a clear inhibition of liver decarboxylase and 3-hydroxy-3-methylglutaryl-CoA reductase. To our knowledge, this is the first report on the in vitro inhibition of both liver regulatory enzymes of cholesterogenesis in phenylketonuria-like conditions. Our results show a lower inhibition of decarboxylase than that of reductase but suggest an important regulatory role of decarboxylase in cholesterol synthesis.


Subject(s)
Carboxy-Lyases/antagonists & inhibitors , Cholesterol/biosynthesis , Hydroxymethylglutaryl-CoA Reductase Inhibitors , Liver/drug effects , Phenylalanine/pharmacology , Animals , Carbon Dioxide/analysis , Carboxy-Lyases/analysis , Chickens , Hydroxymethylglutaryl CoA Reductases/analysis , Liver/enzymology , Male , Mevalonic Acid/metabolism , Phenylacetates/pharmacology , Phenylpyruvic Acids/pharmacology , Phosphorylation/drug effects
14.
Arch Int Physiol Biochim Biophys ; 99(2): 165-8, 1991 Apr.
Article in English | MEDLINE | ID: mdl-1713501

ABSTRACT

Mevalonate-activating enzymes from chick brain and liver were stable when 105,000 x g supernatants were stored at -4 degrees C for 168 h. Mevalonate kinase and mevalonate 5-phosphate kinase retained their activities for 72 h at 4 degrees C while mevalonate 5-pyrophosphate decarboxylase activity significantly decreased after 24-48 h of storage at 4 degrees C. Direct addition of 2.5 mM phenylpyruvate to the reaction mixture produced a significant inhibition of decarboxylase activity in brain and liver. When enzyme preparations were preincubated with 2.5 mM phenylpyruvate for 20 min before the addition of substrate, an increased inhibition was observed. Mevalonate kinase and mevalonate 5-phosphate kinase from both tissues were not affected in the same conditions. The inhibition of brain and liver decarboxylase was progressive with increasing concentrations (2.5-10.0 mM) of phenylpyruvate. No significant difference was observed in the inhibition of decarboxylase after 10 or 20 min of preincubation.


Subject(s)
Brain/enzymology , Liver/enzymology , Mevalonic Acid/metabolism , Phenylpyruvic Acids/pharmacology , Animals , Chickens , Male
15.
Lipids ; 26(1): 77-80, 1991 Jan.
Article in English | MEDLINE | ID: mdl-2051888

ABSTRACT

Very small sample sizes frequently become the limiting factor in biochemical and biomembrane studies in which routine quantification of protein and bulk lipids are required. The procedure described here allows the simultaneous determination of protein and lipid without initial, multiple aliquots. The method is based on the quantitative precipitation of proteins from a defined hexane/isopropanol mixture. The liquid phase resulting after decanting and concentrating to dryness can then be used to assay the lipid content directly. Quantitative assay of protein can be achieved after resuspension of the pelleted material by addition of sodium dodecyl sulfate (0.1%) and deoxycholate (1%). The method is also applicable to other types of lipid- and protein-containing samples with a broad range of protein/lipid ratios and lipid compositions, as they occur, for example, in serum lipoproteins.


Subject(s)
Cell Membrane/chemistry , Lipids/analysis , Proteins/analysis , 1-Propanol , Animals , Chemical Precipitation , Chickens , Cholesterol/analysis , Hexanes , Lipoproteins/blood , Male , Membrane Lipids/analysis , Membrane Proteins/analysis , Microsomes, Liver/chemistry , Phospholipids/analysis
16.
Life Sci ; 49(1): 15-21, 1991.
Article in English | MEDLINE | ID: mdl-1646920

ABSTRACT

The in vivo dipyridamole treatment for 16 days produced a significant decrease in chick plasma cholesterol, mainly due to the esterified form. This effect was especially patent in the VLDL + LDL fraction. Similar results were observed in triglyceride content. To our knowledge, this is the first report on this hypolipidemic effects of dipyridamole. Total and esterified cholesterol increased after the same treatment in chick liver, while brain cholesterol content was not affected. Hepatic 3-hydroxy-3- methylglutaryl-CoA reductase activity was drastically reduced, while other secondary regulatory enzymes such as mevalonate kinase, mevalonate 5-phosphate kinase and mevalonate 5-pyrophosphate decarboxylase did not change significantly. No significant differences were found in cholesterol and lipidic phosphorus from liver microsomes, so that the effect of dipyridamole on reductase activity cannot be due to modifications in cholesterol/lipidic phosphorus molar ratio. Neither of these enzyme activities was affected in vitro by dipyridamole.


Subject(s)
Cholesterol/biosynthesis , Dipyridamole/pharmacology , Hypolipidemic Agents , Phosphotransferases (Alcohol Group Acceptor) , Phosphotransferases (Phosphate Group Acceptor) , Animals , Carboxy-Lyases/metabolism , Chickens , Cholesterol/blood , Hydroxymethylglutaryl CoA Reductases/metabolism , Male , Microsomes, Liver/chemistry , Microsomes, Liver/drug effects , Phosphotransferases/metabolism
17.
Neurochem Int ; 18(2): 171-4, 1991.
Article in English | MEDLINE | ID: mdl-20504690

ABSTRACT

Phenylalanine and its phenyl metabolites produced a clear inhibition of chick brain mevalonate 5-pyrophosphate decarboxylase, while mevalonate kinase and mevalonate 5-phosphate kinase were not significantly affected. Phenolic derivatives produced a similar or higher inhibition than that found in the presence of phenyl metabolites. The inhibition was progressive with increasing concentrations of inhibitors (1.25-5.00 mM). Phenylpyruvate and p-hydroxyphenyl-lactate were the most potent inhibitors of decarboxylase activity. Simultaneous supplementation of each metabolite at 0.25 mM concentration produced a considerable inhibition of brain decarboxylase and 3-hydroxy-3-methylglutaryl-CoA reductase. At our knowledge this is the first report on the in vitro inhibition of both brain regulatory enzymes of cholesterogenesis in phenylketonuric-like conditions.

18.
Arch Int Physiol Biochim ; 98(1): 1-6, 1990 Mar.
Article in English | MEDLINE | ID: mdl-1692683

ABSTRACT

The influence of different diets on cholesterol content of liver and muscle of European eel (Anguilla anguilla) was studied for the first time. In control eel, cholesterol constituted near 7.5% of total lipids in liver and about 1% in muscle. Feeding herring meal-55% diet produced a drastic increase in hepatic cholesterol after a 30 d period. In muscle, cholesterol content also increased after any dietary treatment. Free cholesterol represented about 34% of total cholesterol in liver and about 50% in muscle. In both tissues, these percentages increased after any experimental condition assayed. The n-3/n-6 ratio in the fatty acid composition was manifestly low in herring meal-55% diet, mainly due to the minimal amount of total n-3 fatty acids. This fact may account for the increase in liver cholesterol, bearing in mind the hypocholesterolemic effect of the polyunsaturated n-3 fatty acids.


Subject(s)
Cholesterol/analysis , Diet , Eels/metabolism , Fatty Acids/administration & dosage , Liver/analysis , Muscles/analysis , Animals , Fatty Acids/analysis
19.
Life Sci ; 46(6): 397-403, 1990.
Article in English | MEDLINE | ID: mdl-2154659

ABSTRACT

The in vivo effect of clofibrate on the main regulatory enzymes of cholesterogenesis has been comparatively studied for the first time in chick liver and brain. 3-Hydroxy-3-methylglutaryl-CoA reductase and mevalonate 5-pyrophosphate decarboxylase from chick liver were significantly inhibited by this hypocholesterolenic drug, while mevalonate kinase and mevalonate 5-phosphate kinase were not affected. No enzyme from chick brain was significantly inhibited by the in vivo treatment. However, both liver and brain reductase activity was inhibited in vitro by clofibrate, inhibition that was progressive with increasing concentrations (1.25-5.00 mM) of drug.


Subject(s)
Brain/drug effects , Cholesterol/biosynthesis , Clofibrate/pharmacology , Hydroxymethylglutaryl-CoA Reductase Inhibitors , Liver/drug effects , Phosphotransferases (Alcohol Group Acceptor) , Phosphotransferases (Phosphate Group Acceptor) , Animals , Brain/enzymology , Carboxy-Lyases/antagonists & inhibitors , Liver/enzymology , Male , Phosphotransferases/antagonists & inhibitors
20.
Arch Int Physiol Biochim ; 97(1): 117-21, 1989 Feb.
Article in English | MEDLINE | ID: mdl-2475082

ABSTRACT

The influence of diet protein content (35-45-55%) on growth and lipid composition of muscle and liver of European eel (Anguilla anguilla) was studied for the first time. In control eel, triacylglycerols constituted about 90% of total lipids in muscle and about 40% in liver. Triacylglycerol content in eel muscle significantly increased after two months of treatment with any diet assayed, with independence of protein content and source. In liver, this increase was comparatively higher in herring meal diets. Total phospholipid content in both muscle and liver drastically decreased after one month of all the experimental treatments, although some recuperation was found at the second month. No significant differences in lipid composition of muscle eel were found among the various experimental groups, in spite of the differences observed in the body weight gain.


Subject(s)
Anguilla/metabolism , Dietary Proteins/administration & dosage , Lipid Metabolism , Anguilla/growth & development , Animals , Liver/growth & development , Liver/metabolism , Muscle Development , Muscles/metabolism , Phospholipids/metabolism , Triglycerides/metabolism
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