scholarly journals Inhibitory effects of some long-chain unsaturated fatty acids on mitochondrial β-oxidation. Effects of streptozotocin-induced diabetes on mitochondrial β-oxidation of polyunsaturated fatty acids

1985 ◽  
Vol 230 (2) ◽  
pp. 329-337 ◽  
Author(s):  
H Osmundsen ◽  
K Bjørnstad
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Reductase Activity ◽  
Liver Mitochondria ◽  
Inhibitory Effect ◽  
Diabetic Rats ◽  
Inhibitory Property ◽  
Streptozotocin Induced Diabetes ◽  
Streptozotocin Diabetic Rats ◽  
Coa Reductase

Evidence showing that some unsaturated fatty acids, and in particular docosahexaenoic acid, can be powerful inhibitors of mitochondrial β-oxidation is presented. This inhibitory property is, however, also observed with the cis- and trans-isomers of the C18:1(16) acid. Hence it is probably the position of the double bond(s), and not the degree of unsaturation, which confers the inhibitory property. It is suggested that the inhibitory effect is caused by accumulation of 2,4-di- or 2,4,7-tri-enoyl-CoA esters in the mitochondrial matrix. This has previously been shown to occur with these fatty acids, in particular when the supply of NADPH was limiting 2,4-dienoyl-CoA reductase (EC 1.3.1.-) activity [Hiltunen, Osmundsen & Bremer (1983) Biochim. Biophys. Acta 752, 223-232]. Liver mitochondria from streptozotocin-diabetic rats showed an increased ability to β-oxidize 2,4-dienoyl-CoA-requiring acylcarnitines. Docosahexaenoylcarnitine was also found to be less inhibitory at lower concentrations with incubation under coupled conditions. With uncoupling conditions there was little difference between mitochondria from normal and diabetic rats in these respects. This correlates with a 5-fold stimulation of 2,4-dienoyl-CoA reductase activity found in mitochondria from streptozotocin-diabetic rats.

Effect of glucose or fructose feeding on cholesterol synthesis in diabetic animals

1985 ◽  
Vol 249 (5) ◽  
pp. G634-G641 ◽  
Author(s):  
K. R. Feingold ◽  
A. H. Moser
Keyword(s):  
Cholesterol Synthesis ◽  
Reductase Activity ◽  
Active Form ◽  
Diabetic Rats ◽  
Hepatic Cholesterol ◽  
Hmg Coa Reductase ◽  
Hepatic Cholesterol Synthesis ◽  
Streptozotocin Induced Diabetes ◽  
Intestinal Hypertrophy ◽  
Coa Reductase

Previous studies have demonstrated that cholesterol synthesis is increased twofold in the small intestines of rats with streptozotocin-induced diabetes. The purpose of the present study was to determine the effect of adding glucose or fructose to standard rat chow on cholesterol synthesis in control and diabetic rats. In control rats a 25% glucose or fructose diet fed for 21 days markedly inhibited hepatic cholesterol synthesis in the liver. In contrast, in diabetic animals only fructose inhibited hepatic cholesterol synthesis. In both control and diabetic animals the addition of these simple sugars to the diet did not markedly alter extrahepatic cholesterol synthesis. The enhancement of small intestinal cholesterol synthesis observed in diabetic animals was present regardless of the dietary manipulations. Further studies demonstrated that the addition of smaller concentrations of fructose (10%) to standard rat chow decreased hepatic cholesterol synthesis in both control and diabetic rats. Similarly the addition of fructose to the diet of control and diabetics for a period as short as 2 days was also sufficient to inhibit hepatic cholesterol synthesis. In both control and diabetic animals, fructose feeding decreased hepatic 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity but did not alter the percentage of HMG-CoA reductase in the active form. Finally, the intestinal hypertrophy and stimulation of intestinal cholesterogenesis that are characteristic of streptozotocin-induced diabetes occurred when either glucose or fructose was the sole caloric source.

scholarly journals β-oxidation of polyunsaturated fatty acids with conjugated double bonds. Mitochondrial metabolism of octa-2,4,6-trienoic acid

1989 ◽  
Vol 264 (1) ◽  
pp. 47-52 ◽  
Author(s):  
H Y Wang ◽  
H Schulz
Keyword(s):  
Fatty Acids ◽  
Polyunsaturated Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Liver Mitochondria ◽  
Trienoic Acid ◽  
Rat Liver Mitochondria ◽  
Double Bonds ◽  
Beta Oxidation ◽  
Rat Heart Mitochondria ◽  
Coa Reductase

The mitochondrial beta-oxidation of octa-2,4,6-trienoic acid was studied with the aim of elucidating the degradation of unsaturated fatty acids with conjugated double bonds. Octa-2,4,6-trienoic acid was found to be a respiratory substrate of coupled rat liver mitochondria, but not of rat heart mitochondria. Octa-2,4,6-trienoyl-CoA, the product of the inner-mitochondrial activation of the acid, was chemically synthesized and its degradation by purified enzymes of beta-oxidation was studied spectrophotometrically and by use of h.p.l.c. This compound is a substrate of NADPH-dependent 2,4-dienoyl-CoA reductase or 4-enoyl-CoA reductase (EC 1.3.1.34), which facilitates its further beta-oxidation. The product obtained after the NADPH-dependent reduction of octa-2,4,6-trienoyl-CoA and one round of beta-oxidation was hex-4-enoyl-CoA, which can be completely degraded via beta-oxidation. It is concluded that polyunsaturated fatty acids with two conjugated double bonds extending from even-numbered carbon atoms can be completely degraded via beta-oxidation because their presumed 2,4,6-trienoyl-CoA intermediates are substrates of 2,4-dienoyl-CoA reductase.

Effects of fenofibrate and insulin on the biosynthesis of unsaturated fatty acids in streptozotocin diabetic rats

2005 ◽  
Vol 73 (5) ◽  
pp. 369-378 ◽  
Author(s):  
Mauro A. Montanaro ◽  
Ana M. Bernasconi ◽  
Marìa S. González ◽  
Omar J. Rimoldi ◽  
Rodolfo R. Brenner
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Diabetic Rats ◽  
Streptozotocin Diabetic Rats

scholarly journals Oxidation of cis-5-unsaturated fatty acids in intact rat liver mitochondria: the operation of reduction pathways

1995 ◽  
Vol 308 (1) ◽  
pp. 39-44 ◽  
Author(s):  
K Y Tserng ◽  
S J Jin
Keyword(s):  
Fatty Acids ◽  
Rat Liver ◽  
Capillary Column ◽  
Unsaturated Fatty Acids ◽  
Direct Reduction ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Capillary Column Gas Chromatography ◽  
Coa Reductase ◽  
Direct Quantification

The metabolism of cis-5 unsaturated fatty acids was studied in intact rat liver mitochondria to assess the operation of a reduction pathway. By using direct quantification of metabolites with a capillary-column gas chromatography, 3-hydroxydodecanoate was identified among other metabolites when cis-5-dodecenoate was metabolized in intact rat liver mitochondria. The formation of 3-hydroxydodecanoate supports the existence of a reduction pathway in the metabolism of cis-5-unsaturated fatty acids. This metabolite cannot be produced from the conventional isomerase-mediated pathway. However, the data also indicated the possible operation of the conventional isomerase-mediated pathway in intact rat liver mitochondria. The reduction pathway appears to account for at least 61% of the pathway for cis-5-dodecenoate. This reduction pathway was likely to proceed from the dehydrogenation to trans-2,cis-5-dodecadienoyl-CoA, which was isomerized to delta 3, delta 5-dodecadienoyl-CoA, then to trans-2,trans-4-dodecadienoate. The reduction was mediated by 2,4-dienoyl-CoA reductase by the conversion of trans-2,trans-4-dodecadienoyl-CoA into trans-3-dodecenoyl-CoA. However, direct reduction of the cis-5 double bond was also shown to be operating, although to a lesser extent.

Oxidation and Phosphorylation in Liver Mitochondria from Alloxan and Streptozotocin Diabetic Rats

1971 ◽  
Vol 137 (3) ◽  
pp. 992-995 ◽  
Author(s):  
C. R. Mackerer ◽  
R. J. Paquet ◽  
M. A. Mehlman ◽  
R. B. Tobin
Keyword(s):  
Liver Mitochondria ◽  
Diabetic Rats ◽  
Streptozotocin Diabetic Rats

scholarly journals Regulation of very-low-density-lipoprotein lipid secretion in hepatocyte cultures derived from diabetic animals

1989 ◽  
Vol 262 (1) ◽  
pp. 313-319 ◽  
Author(s):  
J M Duerden ◽  
S M Bartlett ◽  
G F Gibbons
Keyword(s):  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Inhibitory Effect ◽  
Diabetic Rats ◽  
Whole Body ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Short Period ◽  
Streptozotocin Diabetic Rats ◽  
Cholesterol Secretion

Hepatocytes were derived from 2-3-day streptozotocin-diabetic rats and maintained in culture for up to 3 days. Compared with similar cultures from normal animals, these hepatocytes secreted less very-low-density-lipoprotein (VLDL) triacylglycerol, but the decrease in the secretion of VLDL non-esterified and esterified cholesterol was not so pronounced. This resulted in the secretion of relatively cholesterol-rich VLDL particles by the diabetic hepatocytes. Addition of insulin for a relatively short period (24 h) further decreased the low rates of VLDL triacylglycerol secretion from the diabetic hepatocytes. The secretion of VLDL esterified and non-esterified cholesterol also declined. These changes occurred irrespective of whether or not exogenous fatty acids were present in the culture medium. Little or no inhibitory effect of insulin was observed after longer-term (24-48 h) exposure to the hormone. Both dexamethasone and a mixture of lipogenic precursors (lactate plus pyruvate) stimulated VLDL triacylglycerol and cholesterol secretion, but not to the levels observed in hepatocytes from normal animals. The low rate of hepatic VLDL secretion in diabetes contrasts with the increase in whole-body VLDL production rate. This suggests that the intestine is a major source of plasma VLDL in insulin-deficient diabetes.

scholarly journals Inhibition of steroid 5α-reductase by specific aliphatic unsaturated fatty acids

1992 ◽  
Vol 285 (2) ◽  
pp. 557-562 ◽  
Author(s):  
T Liang ◽  
S Liao
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Linoleic Acid ◽  
Linolenic Acid ◽  
Unsaturated Fatty Acids ◽  
Binding Assay ◽  
Reductase Activity ◽  
Undecylenic Acid ◽  
Gamma Linolenic Acid ◽  
Enzymic Assay

Human or rat microsomal 5 alpha-reductase activity, as measured by enzymic conversion of testosterone into 5 alpha-dihydrotestosterone or by binding of a competitive inhibitor, [3H]17 beta-NN-diethulcarbamoyl-4-methyl-4-aza-5 alpha-androstan-3-one ([3H]4-MA) to the reductase, is inhibited by low concentrations (less than 10 microM) of certain polyunsaturated fatty acids. The relative inhibitory potencies of unsaturated fatty acids are, in decreasing order: gamma-linolenic acid greater than cis-4,7,10,13,16,19-docosahexaenoic acid = cis-6,9,12,15-octatetraenoic acid = arachidonic acid = alpha-linolenic acid greater than linoleic acid greater than palmitoleic acid greater than oleic acid greater than myristoleic acid. Other unsaturated fatty acids such as undecylenic acid, erucic acid and nervonic acid, are inactive. The methyl esters and alcohol analogues of these compounds, glycerols, phospholipids, saturated fatty acids, retinoids and carotenes were inactive even at 0.2 mM. The results of the binding assay and the enzymic assay correlated well except for elaidic acid and linolelaidic acid, the trans isomers of oleic acid and linoleic acid respectively, which were much less active than their cis isomers in the binding assay but were as potent in the enzymic assay. gamma-Linolenic acid had no effect on the activities of two other rat liver microsomal enzymes: NADH:menadione reductase and glucuronosyl transferase. gamma-Linolenic acid, the most potent inhibitor tested, decreased the Vmax. and increased Km values of substrates, NADPH and testosterone, and promoted dissociation of [3H]4-MA from the microsomal reductase. gamma-Linolenic acid, but not the corresponding saturated fatty acid (stearic acid), inhibited the 5 alpha-reductase activity, but not the 17 beta-dehydrogenase activity, of human prostate cancer cells in culture. These results suggest that unsaturated fatty acids may play an important role in regulating androgen action in target cells.

scholarly journals Amelioration of neuropilin-1 and rage/matrix metalloproteinase-2 pathway-induced renal injury in diabetic rats by rosuvastatin

2021 ◽  
pp. 21-21
Author(s):  
Rabia Nabi ◽  
Sultan Alvi ◽  
Sultan Alouffi ◽  
Saif Khan ◽  
Adnan Ahmad ◽  
...  
Keyword(s):  
Matrix Metalloproteinase ◽  
Renal Injury ◽  
Reductase Activity ◽  
Renal Tissue ◽  
Diabetic Rats ◽  
Paraoxonase 1 ◽  
Matrix Metalloproteinase 2 ◽  
Altered Level ◽  
Neuropilin 1 ◽  
Coa Reductase

Advanced glycation end-products (AGEs) induce the production of reactive oxygen species (ROS) and extra cellular matrix (ECM) degradation via suppression of neuropilin-1 (NRP-1) and interaction with AGE-receptors (RAGE). This study aimed to reveal whether modulation of NRP-1 by rosuvastatin (RT) prevents AGE-induced renal injury via targeting RAGE/matrix metalloproteinase-2 (MMP-2) signaling in diabetic rats. Treatment with RT ameliorated the altered level of markers of glycemic control, renal injury, cholesterol, triglyceride (TG) and hepatic HMG-CoA reductase activity; the level of circulatory carboxymethyl-lysine (CML) and the accumulation of fluorogenic-AGEs in renal tissue was reduced; the expression of renal NRP-1, a checkpoint target, was stimulated; the transcription of RAGE, NF?B-2, TGF-?1 and MMP-2 was suppressed; the circulatory carbonyl content (CC) and paraoxonase-1 (PON-1) activity was ameliorated, and renal histopathological features were attenuated as evidenced by improved glomerular appearance, Bowman?s space and abundant podocytes in kidneys. In conclusion, RT exhibited the potential to counteract diabetes and AGE-induced renal pathologies via stimulation of NRP-1, suppression of RAGE, and of genes responsible for ECM disintegration (MMP-2) and the inflammatory response (NF?B-2).

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