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)

Typical metabolic patterns are detectable in the livers of growing rats after feeding diets with high (25%) or low (2%) fat contents. In view of the elucidation of problems related to the regulation of the metabolic processes, it is of interest to know in what way these metabolic patterns change after short-time change from the one diet to the other and if there are hierarchies. Within 2 days after change of diet, the enzymes glucose-6-phosphate dehydrogenase, NAD-malate dehydrogenase, lactate dehydrogenase, citrate synthase and fatty acid synthase were affected, only the 3'.5'-c AMP-splitting phosphodieterase showed no change. The metabolites lactate and pyruvate also changed, inversely to lactate dehydrogenase activity, the lactate-pyruvate ratio remaining almost constant. Acetyl CoA also responded in a characteristic manner. The single parameters were differently affected by the kind of the change of diet (from high-fat to low-fat diet or inversely). For example, glucose-6-phosphate dehydrogenase responded very rapidly to the change from the high-fat to the low-fat diet, malate dehydrogenase behaved inversely, and citrate synthase responded to both changes. Consequently, the regulatory processes after change of diet start from different sides. It is thinkable that this behaviour is related to the different roles of the determined parameters in fat and energy metabolism.
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PMID:[Behavior of certain parameters of lipid and energy metabolism. 5. Effects of high-fat and low-fat diets on certain biochemical parameters in rat livers before and after change of diet]. 21 48

To characterize the lipid and the energy metabolism in the livers of genetically different types of pigs (land race pig and mini pig), the authors determined the activities of enzymes typical of and limiting these metabolic pathways. Furthermore, they measured the concentrations of typical metabolites and ascertained parameters that are of importance in energy metabolism. The concentrations of acetyl CoA and free fatty acids in the livers of mini pigs were significantly greater than those in the livers of land race pigs, whereas the cholesterol, glycerol, triglyceride and acetoacetate concentrations were reduced. The activities of glucose-6-phosphate dehydrogenase (E.C.1.1.1.49.), citrate synthase (E.C.4.1.3.7.) and ATP citrate lyase (E.C.4.1.3.8.) were lower in the livers of mini pigs than in the livers of land race pigs, whereas the activity of fatty acid synthase was higher. The concentrations of cyclic 3',5'-adenosine monophosphate (AMP) and adenosine diphosphate (ADP) were lower in the livers of mini pigs than in those of land race pigs. In land race pigs, the metabolic process seems, therefore, to be determined in favour of the degradation of free fatty acids and of the generation of energy. In mini pigs, lipogenesis in the liver appears to be the decisive metabolic pathway. The possibility of a higher coordinating control mechanism of the lipid and the energy metabolism is discussed.
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PMID:[Behavior of certain parameters of lipid and energy metabolism. IV. Regulation of lipid and energy metabolism in livers and race and mini pigs]. 84 65

In continuation of previous investigations, the authors studied the behaviour of the activities of certain enzymes (citrate synthase, adenosine triphosphate citrate lyase, fatty acid synthase and glucose-6-phosphate dehydrogenase) in the livers of growing rats on diets differing in fat content. A high-fat diet resulted in a reduction of the activities of fatty acid synthase, glucose-6-phosphate dehydrogenase and adenosine triphosphate citrate lyase, whereas the activity of citrate synthase increased, which is interpreted in the sense of an acceleration of the introduction of acetyl residues into the citrate cycle for the purpose of oxidative final degradation, and as a removal of acetyl CoA for the purpose of fatty acid synthesis.
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PMID:[Behavior of some parameters of lipid and energy metabolism. 2. Activity of citrate synthase, ATP citrate lyase, fatty acid synthase, and glucose-6-phosphate dehydrogenase in liver of growing rats on diets differing in fat content]. 95 60

This investigation concerns the effects of the level of intake of a high carbohydrate diet on transcriptional rate, mRNA concentration and enzyme induction for lipogenic enzymes in rat liver. Six hours after refeeding fasted rats, the transcriptional rates in livers reached low maximum levels with small quantities of diet, but the mRNA concentrations continued to increase as diet intake increased. Greater diet intake primarily increased transcriptional rates and mRNA concentrations of lipogenic enzymes. After refeeding for 16 h, the mRNA concentrations were sigmoidly increased relative to the diet quantity and reached maximum levels of 20-, 110-, 22- and 16-fold above each fasted level for acetyl-CoA carboxylase, fatty acid synthase, malic enzyme and glucose-6-phosphate dehydrogenase, respectively. After 3 d of refeeding (in a steady state of lipogenic enzyme activities), however, the transcriptional rates, mRNA concentrations and activity inductions of all the enzymes were sigmoidly increased relative to diet quantity, but were not different among the enzymes. Consequently, fatty acid synthesis and triglyceride levels in the liver were not increased by feeding less than 70% of ad libitum intake but were greatly increased by feeding greater than 70% of ad libitum intake.
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PMID:Regulation of hepatic lipogenic enzyme gene expression by diet quantity in rats fed a fat-free, high carbohydrate diet. 134 47

The effects of nutrients and hormones on the mRNA levels of acetyl-CoA carboxylase, fatty acid synthase, malic enzyme, and glucose 6-phosphate dehydrogenase were examined in primary cultures of rat hepatocytes during the process of induction. The addition of both glucose and insulin to the culture medium markedly enhanced the lipogenic enzyme mRNA induction due to either of them, in 16 h. Fructose or glycerol proved to be an effective substitute for glucose, suggesting that glycolytic metabolites were involved in the mRNA induction. It is remarkable that mRNA induction of acetyl-CoA carboxylase was the most sensitive to glucose and also to insulin among the lipogenic enzymes. Polyunsaturated fatty acids markedly reduced the mRNA induction of lipogenic enzymes. Dexamethasone enhanced all the lipogenic enzyme mRNA induction by insulin. On the other hand, triiodothyronine addition greatly increased the mRNA concentrations of lipogenic enzymes, but dexamethasone decreased rather than increased the mRNA induction by triiodothyronine. The effects of insulin on the induction of the lipogenic enzyme mRNAs were similar, but those of triiodothyronine were not. Triiodothyronine markedly enhanced malic enzyme mRNA induction by insulin with dexamethasone, and tended to enhance the induction of the acetyl-CoA carboxylase and fatty acid synthase mRNAs, but not that of glucose 6-phosphate dehydrogenase mRNA. It appeared that insulin and triiodothyronine synergistically enhanced lipogenic enzyme mRNA induction by glucose, but the mechanisms were different.
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PMID:Nutritional and hormonal regulation of mRNA levels of lipogenic enzymes in primary cultures of rat hepatocytes. 135 82

1. Brown adipose tissue (BAT) and liver lipogenesis in vivo estimated by using 3H2O as tracer was very low and did not change significantly between 10 and 20 days after birth. Lipogenesis increased dramatically in both tissues by weaning at 20 days, peaking between 25 and 30 days of age. Since that time the rate of fatty acid synthesis in BAT decreased gradually to reach adult level after 2 months, whereas in the liver there was a sharp decrease of lipogenesis. 2. The activities of fatty acid synthase, citrate cleavage enzyme, malic enzyme and glucose 6-phosphate dehydrogenase essentially followed a similar course of developmental changes as lipogenesis. 3. In contrast to the enzymes listed above NADP-linked isocitrate dehydrogenase remained unaltered over the period studied, whereas lactate and malate dehydrogenases exhibited very high activity at 10 days after birth and from then decreased to reach adult level at the age of about 20 days. 4. The data obtained indicate that no substantial differences could be detected in the developmental pattern of lipogenesis and lipogenic enzyme activities between BAT and liver up to 30 days of age but after this time these processes were not co-ordinated in both tissues. Beyond this time the BAT was characterized by a much higher rate of lipogenesis than the liver. 5. The results are discussed in terms of the nutrient changes and the relationship between thermogenesis and lipogenesis in BAT.
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PMID:Developmental changes of lipogenic enzyme activities and lipogenesis in brown adipose tissue and liver of the rat. 149 75

The diurnal variations in mRNA quantities of lipogenic enzymes (acetyl-CoA carboxylase, fatty acid synthase, malic enzyme and glucose-6-phosphate dehydrogenase) in rat livers were detected. When the rats began feeding actively after lights out at 1900 h, the mRNA quantities were high from 0500 h to 0900 h in the morning. The variation in fatty acid synthase mRNA quantities was the most dramatic. However, no measurable variation in any enzyme levels including fatty acid synthase was detected. It may be because the half-lives of the enzymes are too long to be effected by the mRNAs which were high for several hours.
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PMID:Diurnal variations of lipogenic enzyme mRNA quantities in rat liver. 168 92

Food intake, plasma glucose, insulin (I) and triiodothyronine (T3) and liver glucose 6-phosphate dehydrogenase (G6P-DH), malic enzyme (ME). ATP-citrate lyase, acetyl-CoA carboxylase (AcCoACx) and fatty acid synthase (FAS) activities were measured in 2 and 22 months old rats before, after 3 d starvation and 2,4,6. 24 and 48 h refeeding a high carbohydrate (74% w/w) diet. Expressed per 100 g of body weight, the carbohydrate intake of old rats was 55% lower than that of young rats. Plasma insulin was higher in old than in young rats and decreased (-40%) after starvation and returned to control values 4 h after refeeding. In young rats plasma insulin fell after starvation (-85%) and returned to normal values 2 h after refeeding. No significant differences were observed in plasma [T3] between the two groups. During the first 6 h of refeeding, plasma glucose increased 2-fold and returned to control values after 24 h in young rats. In old rats, plasma glucose returned to its control value after 2 h. Compared to the starved level, 48 h after refeeding, G6P-DH, ME, ATP-citrate lyase, AcCoACx and FAS activities increased 5- to 6-fold in young rats, while in old rats the increase was much smaller and represented 35% of that observed in young rats. These results suggest, that the age-related reduction in inducibility of hepatic lipogenic enzymes of rats refed a high carbohydrate diet after starvation may be due to a spontaneous decrease in the carbohydrate intake and to a decrease effectiveness of insulin (insulin resistance).
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PMID:Age-dependent hepatic lipogenic enzyme activities in starved-refed rats. 197 51

Energy intake, weight gain, carcass composition, plasma fuels, hepatic metabolites and lipogenic enzyme activities were studied in adult rats fed either a low fat, high carbohydrate (LF) diet or one of two fat-containing diets in which 32% of the metabolizable energy was constituted by long-chain triglycerides (LCT) or medium-chain triglycerides (MCT). Compared with the LF diet, the MCT diet did not depress food and energy intake, weight gain, energy and nitrogen retention or lipid deposition and did not produce ketogenesis. The weight gain of rats fed LCT was 25% higher, and increased lipid deposition was observed. Lower lipogenic enzyme activities were observed in rats fed the LF diet containing 4% corn oil than in rats fed the MCT diet containing 1% corn oil. This effect disappeared when rats previously adapted to the LCT diet were fed LF or MCT diets containing 1% corn oil for 21 d. By d 21, in both groups, hepatic malic enzyme, ATP-citrate lyase, acetyl CoA carboxylase and fatty acid synthase activities were 2.2-, 2.0-, 2.3- and 1.8-fold higher than those of rats fed LCT. Intermediate hepatic glucose-6-phosphate dehydrogenase activities were observed in rats fed the MCT diet, compared with LCT (40% lower) and LF (1.6-fold higher) diets. These data show that in rats fed a diet in which MCT supplies 32% of metabolizable energy, a high activity of lipogenic enzymes is observed, suggesting that MCT had no inhibitory effect on the activity of these enzymes.
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PMID:Metabolic effects in rats of a diet with a moderate level of medium-chain triglycerides. 201 68

The present study was undertaken to determine the effects of porcine growth hormone (pGH) on glucose transport, to establish which lipogenic enzymes were affected by pGH, and to determine if changes in insulin binding or insulin receptor kinase activity contributed to the diminished insulin responsiveness of adipocytes from pigs treated with pGH. Pigs were treated with pGH daily (70 micrograms/kg body wt.) for 7 days. pGH treatment reduced the basal (non-insulin-stimulated) glucose transport rate by 62% and the insulin-stimulated transport rate by 47%. The decline in glucose transport rate was paralleled by a 64% decrease in fatty acid synthesis. The reduction in the lipogenic rate was associated with a marked decline in the activity of several lipogenic enzymes: glucose-6-phosphate dehydrogenase (50% decrease), 6-phosphogluconate dehydrogenase (11% decrease), malic enzyme (62% decrease) and fatty acid synthase (activity not detectable after pGH treatment). The pGH-dependent decline in insulin responsiveness was not associated with any change in the binding of insulin to intact adipocytes or to plasma membrane preparations. The insulin-stimulated tyrosine kinase activity of the wheat-germ agglutinin-purified receptors from pGH-treated adipocytes was not different from that in control adipocytes, except when high concentrations of insulin were employed. These findings establish that pGH elicits a number of metabolic effects in porcine adipocytes which collectively diminish the rate of lipid synthesis, and thereby contribute to the decrease in lipid deposition observed in pGH-treated pigs. Furthermore, the pGH-dependent impairment in insulin action appears to be mediated at some location distal to the receptor kinase step or in other signal pathway(s) which mediate the biological effects of insulin that are not dependent on activation of insulin receptor tyrosine kinase activity.
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PMID:The inhibition of insulin action and glucose metabolism by porcine growth hormone in porcine adipocytes is not the result of any decrease in insulin binding or insulin receptor kinase activity. 215 2


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