Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.1.1.49 (glucose-6-phosphate dehydrogenase)
 7,794 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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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PMID:Zinc deficiency and activities of lipogenic and glycolytic enzymes in liver of rats fed coconut oil or linseed oil. 776 Jun 90

The lipogenic enzymes fatty acid synthase (FAS; EC 2.3.1.85), citrate cleavage enzyme (CCE; EC 4.1.3.8), malic enzyme (ME; EC 1.1.1.40), glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (PGDH; EC 1.1.1.44) were investigated in liver and in brown adipose tissue (BAT) of Wistar rats under various dietary conditions and in the presence of 15 to 250 ppm (approximately 0.045-0.75 mumol/kg chow) polychlorinated biphenyls (PCBs). In response to refeeding starved animals, enzyme activities in both tissues increased to above normal levels and thereafter exhibited pronounced oscillations of their activities. The extent of increase depended on the carbohydrate and fat content of the diet. The lipogenic enzymes could be grouped in two categories according to their sensitivity to dietary carbohydrate: FAS and CCE responded faster to smaller changes in dietary composition, while ME, G6PDH and PGDH required larger changes and more time to respond. Diet-induced alterations of enzyme activities were of the same order of magnitude in liver and BAT. They were age-dependent, being more pronounced in young animals. Independent of the type of dietary manipulations, activities changed in a coordinate fashion, i.e., the changes of the activities of all 5 enzymes occurred at similar ratios to each other with an identical time course. Feeding PCB-containing diets resulted in a considerable increase of the activities of the lipogenic enzymes in liver, which was significantly greater with ME, G6PDH and PGDH. The effect was dose-dependent but transient. In liver the response to PCB feeding was identical in male and female animals, whereas in BAT lipogenic activities increased in females, but decreased in males. Refeeding starved animals with a PCB-containing diet led to an additional stimulation of the normal refeeding-induced increase of the enzyme activities in liver and BAT. This PCB-induced increase was 2-fold for FAS and CCE, but up to 15-fold for the other enzymes. All PCB-induced effects were significantly less pronounced in old than in young animals. In primary hepatocytes activities increased in hormone-free medium in the presence of PCBs. While activity was induced in insuline- and triiodothyronine-containing medium, this increase was significantly greater with PCBs present.
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PMID:Lipogenic enzymes of rat liver and adipose tissue. Dietary variations and effect of polychlorinated biphenyls. 794 78

It is well known that a carbohydrate-rich diet promotes lipogenesis via induction of hepatic lipogenic enzymes, whereas chronic physical exercise reduces body fat. The purpose of this study was to investigate whether exercise training can decrease diet-induced hepatic lipogenic enzymes and total body fat composition. Female Sprague-Dawley rats were randomly divided into exercise trained (T) and sedentary (S) groups. Training was performed on a treadmill for 8 weeks for up to 25 m/minute, 15% grade for 90 minutes/day, 5 days/week. The T and S groups were further divided into four dietary treatments. Fifty percent of the calories for each diet were from a basal ingredient and the other 50% were from either cornstarch (C), glucose (G), fructose (Fr), or fat (Fa). T significantly decreased body fat and increased body water content in all dietary groups (p < 0.01), but had no effect on body weight. Fr rats had significantly heavier liver weight than did the remaining groups. Activities of hepatic fatty acid synthase, ATP-citrate lyase (CL), malic enzyme (ME), pyruvate kinase, and glucose-6-phosphate dehydrogenase were significantly higher in Fr and lower in Fa compared with C and G. Training significantly increased activities of CL and ME in Fa, but had little effect on these enzymes in other groups. These data suggest that the fat-reducing effect of conventional exercise training is elicited by regulatory mechanisms other than by a reduction of hepatic lipogenic enzymes.
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PMID:Effects of exercise training on diet-induced lipogenic enzymes and body composition in rats. 809 29

The time courses and the regulation of lipogenic enzyme gene expression during development after birth have been investigated. The mRNA concentrations and activities of liver lipogenic enzymes (acetyl-CoA carboxylase, fatty acid synthase, malic enzyme, glucose-6-phosphate dehydrogenase, and ATP-citrate lyase) were very low in all the suckling rats, regardless of dietary fat of the mothers. After weaning to the same diet as the mothers, the mRNA and enzyme levels were greatly increased by the fat-free or hydrogenated fat diet but not so greatly increased by the corn or fish oil diet. The mRNA concentrations of all the groups reached maximum at 4-6 weeks old and then decreased, usually to 40-60% of the maximal levels. It appeared that the gene expression after weaning is subject to strong nutritional regulation, as well as developmental regulation. The plasma levels of triiodothyronine and insulin were low during suckling. Malic enzyme mRNA level was increased by triiodothyronine treatment even during suckling, but the absolute increase was much less than after weaning. Thus, the gene expression of lipogenic enzymes during suckling appeared to be suppressed by nutritional and hormonal regulation, or may not be sufficiently developed. On the other hand, the hepatic triacylglycerol levels were increased slightly at 2 weeks old and greatly at 3 weeks. As the gene expression of lipogenic enzymes was still low at that time, the major triacylglycerols appear to be obtained from milk and accumulated in preparation for weaning.
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PMID:Lipogenic enzyme gene expression in rat liver during development after birth. 810 37

In the present study, we report the long-term metabolic consequences of feeding a milk substitute formula that is high in carbohydrate-derived calories during the suckling period. Male Sprague-Dawley rat pups were raised by gastrostomy on a high carbohydrate (HC) formula or a high fat (HF) formula (which mimicked rat milk composition in macronutrients) during the pre-weaning period (day 4 to 24). These rats were then weaned to a laboratory stock diet and subsequently challenged with a high sucrose diet to augment the development of obesity. The pups receiving the HC formula developed obesity in later life, even though there was no change in the body weight of this group compared to mother-fed (MF) controls or HF formula fed animals during the pre-weaning period. The HC rats were hyperinsulinemic and their growth rates were greater than MF rats starting at day 55. The lipogenic capacity of liver as well as adipose tissues (epididymal and omental) was higher in HC animals compared to MF control animals, as reflected by increases in two key lipogenic enzymes (fatty acid synthase and glucose-6-phosphate dehydrogenase) and in vitro synthesis of lipids. An analysis of adipose tissue morphology in adult rats showed an increase in cell size in epididymal adipose tissue of HC rats compared to the MF group. However, there was no significant difference in cell size in omental adipose tissue between the MF and HC rats. The HF group behaved similarly to the MF control group in growth pattern and measured metabolic parameters.
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PMID:Long-term effects of feeding high carbohydrate diet in pre-weaning period by gastrostomy: a new rat model for obesity. 822 Jun 51

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.
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PMID:Inhibition of lipogenesis in rat brown adipose tissue by clofibrate. 824 Apr 2

The effects of an acute bout of prolonged exhaustive exercise on the activities of hepatic lipogenic enzymes have been investigated. Male Sprague-Dawley rats were randomly divided into three groups: fasted for 48 h without refeeding (FA) and fasted for 48 h and refed a diet high in fructose (RF) or in cornstarch (RC). One-half of each group of rats exercised on a treadmill at 20 m/min, 5% grade, until exhaustion and the other half rested for the same amount of time without food. Dietary intakes during refeeding were kept equal between the exercised and rested control animals. Activities of all hepatic lipogenic enzymes measured, i.e., fatty acid synthase (FAS), L-type pyruvate kinase (L-PK), ATP citrate lyase, malic enzyme, and glucose-6-phosphate dehydrogenase, were induced dramatically by fasting-refeeding and were significantly higher in the RF than in the RC rats (P < 0.05). FAS activity was increased 19- and 39-fold, respectively, in the RC and RF rats compared with the FA rats. Exercise decreased FAS activity to approximately one-third of the resting control value in both RC and RF rats (P < 0.05) but not in FA rats. L-PK activity was elevated by 55% in RC and 100% in RF rats compared with FA rats (P < 0.05). FA and RF rats also showed a reduction of L-PK activity with exercise. No significant alteration of other lipogenic enzymes was observed after exercise.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of acute exercise on hepatic lipogenic enzymes in fasted and refed rats. 856 31

The effects of an acute bout of prolonged exercise on the activities of several hepatic lipogenic enzymes and the abundance of fatty acid synthase (FAS) mRNA were evaluated using a food deprivation-refeeding protocol in which diets contained 50% of the energy from either fructose or cornstarch. Food was withheld from male rats for 48 h and refed for 0, 4, 8, 12, 24 or 48 h. At each time point, half of each dietary group was subjected to a single bout of treadmill running until exhaustion and killed immediately. The other half of each group rested without food for the same amount of time before being killed. Exercise significantly decreased FAS activity by 57, 46, 10, 26 and 70% at 4, 8, 12, 24 and 48 h of refeeding, respectively, in the fructose-fed rats; and by 70 and 63% at 24 and 48 h of refeeding, respectively, in the cornstarch-fed rats. Activities of L-type pyruvate kinase and glucose 6-phosphate dehydrogenase were significantly decreased after exercise in the fructose-fed, but not cornstarch-fed rats. In rested rats, FAS mRNA abundance increased approximately fourfold above the unfed levels after 8 and 12 h of refeeding. Exercise attenuated the diet-induced increases in FAS mRNA abundance. At 8 h of refeeding, both cornstarch- and fructose-fed exercised rats had 71% (P < 0.05) of the FAS mRNA levels of their rested counterparts; at 12 h, these exercised rats showed only 46 and 27% (P < 0.05) of FAS mRNA levels compared with rested rats fed the same diet. We conclude that dietary induction of FAS activity and mRNA abundance can be inhibited by prolonged exercise, suggesting that exercise may influence FAS transcription and/or mRNA stability.
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PMID:Exercise down-regulates hepatic lipogenic enzymes in food-deprived and refed rats. 875 68

Glycogen content as well as glycolytic, gluconeogenic and fatty acid synthesis enzyme activities were monitored in young and adult male rats fed diets differing in fat content: 11% (low), 22% (medium) and 42% (high) of total energy from fat. The results showed significant differences in the responses of young and adult rats to changes in dietary fat and carbohydrate. In young animals, increasing dietary fat decreased total liver glycogen phosphorylase (GP), pyruvate kinase (PK), glycerol 3-phosphate dehydrogenase, glucose 6-phosphate dehydrogenase, malic enzyme (ME), ATP-citrate lyase (ATP-CL) and fatty acid synthase (FAS). Increasing dietary fat also affected enzyme levels in other tissues: hexokinase (HK) and pyruvate dehydrogenase (PDH) activities decreased whereas skeletal muscle PK activity increased. The pattern of enzyme changes was similar in livers of fed adults with the exception that liver GP was not affected by dietary manipulations. Overnight food deprivation decreased liver glucokinase (GK), ME, ATP-CL, and FAS activities and increased liver phosphoenolpyruvate carboxykinase (PEPCK) and phosphofructokinase in both young and adult animals. In young animals, food deprivation also: (i) reduced liver GK and PK, (ii) increased kidney PEPCK, (iii) decreased muscle PEPCK and (iv) decreased kidney PDH. Food-deprived adults had increased skeletal muscle PEPCK and kidney glycogen synthetase as well as decreased kidney PEPCK muscle GP activity. These differences suggest that young animals are somewhat more responsive to changes in dietary manipulations. They also show that overnight food restriction causes a more profound metabolic re-organization in younger than in older animals.
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PMID:Enzymes of carbohydrate metabolism in young and adult rats fed diets differing in fat and carbohydrate. 881 10

Insulin is capable of regulating cellular and metabolic processes as well as gene expression. In recent years, enthusiasm has surfaced for using insulin-mimetics to study the mechanism of action of insulin. Vanadate and selenate are two compounds that have been found to mimic the action of insulin on control of blood glucose levels in vivo. Vanadate has also been shown to regulate the expression of several enzymes both in vivo and in vitro, however, studies concerning selenate's ability to regulate expression have not been reported. In this study we show that administration of vanadate or selenate to streptozotocin-induced diabetic rats not only normalizes blood glucose levels similarly to insulin but also positively affects the expression of two key metabolic enzymes, glucose-6-phosphate dehydrogenase (G6PDH) and fatty acid synthase (FAS). Both G6PDH and FAS activity are significantly decreased in diabetic animals compared to non-diabetic control. Treatment of the diabetic animals with either insulin, vanadate or selenate restored both activities to about 80-90% of control. All treatment conditions exhibited activities significantly higher than those determined for the diabetic group but did not differ significantly from each other. Increases in G6PDH or FAS activity are due to increases in mRNA level. Increase in both G6PDH and FAS mRNA was comparable to the observed increase in activity suggesting that regulation of expression by the mimetics occurs pretranslationally.
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PMID:Insulin-like effects of vanadate and selenate on the expression of glucose-6-phosphate dehydrogenase and fatty acid synthase in diabetic rats. 883 72


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