scholarly journals The redox state of free nicotinamide–adenine dinucleotide phosphate in the cytoplasm of rat liver

1969 ◽  
Vol 115 (4) ◽  
pp. 609-619 ◽  
Author(s):  
R. L. Veech ◽  
L. V. Eggleston ◽  
H. A. Krebs
Keyword(s):  
Malic Enzyme ◽  
Redox State ◽  
Carbohydrate Diet ◽  
Redox States ◽  
Low Carbohydrate Diet ◽  
A Value ◽  
Low Carbohydrate ◽  
Sucrose Diet ◽  
High Sucrose Diet ◽  
High Sucrose

1. The concentrations of the oxidized and reduced substrates of the ‘malic’ enzyme (EC 1.1.1.40) and isocitrate dehydrogenase (EC 1.1.1.42) were measured in freeze-clamped rat livers. By assuming that the reactants of these dehydrogenase systems are at equilibrium in the cytoplasm the [free NADP+]/[free NADPH] ratio was calculated. The justification of the assumption is discussed. 2. The values of this ratio obtained under different nutritional conditions (well-fed, 48hr.-starved, fed with a low-carbohydrate diet, fed with a high-sucrose diet) were all of the same order of magnitude although characteristic changes occurred on varying the diet. The value of the ratio fell on starvation and on feeding with the low-carbohydrate diet and rose slightly on feeding with the high-sucrose diet. 3. The mean values of the ratio were calculated to be between 0·001 and 0·015, which is about 100000 times lower than the values of the cytoplasmic [free NAD+]/[free NADH] ratio. 4. The differences in the redox state of the two nicotinamide–adenine dinucleotide couples can be explained on a simple physicochemical basis. The differences are the result of equilibria that are determined by the equilibrium constants of a number of highly active readily reversible dehydrogenases and transaminases and the concentrations of the substrates and products of these enzymes. 5. The decisive feature is the fact that the NAD and NADP couples share substrates. This sharing provides a link between the redox states of the two couples. 6. The application of the method of calculation to data published by Kraupp, Adler-Kastner, Niessner & Plank (1967), Goldberg, Passonneau & Lowry (1966) and Kauffman, Brown, Passonneau & Lowry (1968) shows that the redox states of the NAD and NADP couples in cardiac-muscle cytoplasm and in mouse-brain cytoplasm are of the same order as those in rat liver. 7. The determination of the equilibrium constant at 38°, pH7·0 and I 0·25 (required for the calculation of the [free NADP+]/[free NADPH] ratio), gave a value of 3·44×10−2m for the ‘malic’ enzyme (with CO2 rather than HCO3− as the reactant) and a value of 1·98×10−2m−1 for glutathione reductase.

scholarly journals Effects of blueberry leaf and stem extracts on hepatic lipid levels in rats consuming a high-sucrose diet

2018 ◽  
Vol 8 (9) ◽  
pp. 447
Author(s):  
Yasushi Matsuura ◽  
Hiroyuki Sakakibara ◽  
Maho Kawaguchi ◽  
Emi Murayama ◽  
Daigo Yokoyama ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Malic Enzyme ◽  
Body Weight Gain ◽  
Hot Water ◽  
Lipid Levels ◽  
Hepatic Lipid ◽  
Sucrose Diet ◽  
Malic Enzyme Activity ◽  
High Sucrose Diet ◽  
High Sucrose

Background: Blueberry stems, a by-product of blueberry leaf tea production, are typically discarded. We evaluated the effects of hot-water extracts of rabbiteye blueberry (Vaccinium virgatum Aiton; RB species) leaves and stems on hepatic lipid levels in rats consuming a high-sucrose diet.Methods: Male Sprague-Dawley rats were divided into groups that received a control high-sucrose diet alone or supplementation with 2.0% blueberry leaf extract or 0.5% or 2.0% blueberry stem extract. Blood and hepatic lipid levels, hepatic lipogenic enzyme activity, and hepatic quercetin metabolites were evaluated after 28 days of ad libitum consumption.Results: Supplementation with the extracts did not affect body weight gain, food intake, liver and white adipose tissue weights, or serum lipid levels. Hepatic triglyceride and total cholesterol levels were reduced in the groups that received 2.0% supplementation of either extract. Hepatic malic enzyme activity was also reduced in those groups. Quercetin and its glycosides, the major polyphenols identified in the extracts, accumulated in the liver as quercetin aglycone and quercetin metabolites. Conclusion: We demonstrated how daily consumption of blueberry leaf and stem extracts can decrease hepatic lipid levels, potentially downregulating malic enzyme activity. These effects were intensive in leaf extracts. The active compounds existed in both extracts may be quercetin and its glycosides. Therefore, blueberry stems and leaves may be an attractive candidate novel functional food.Keywords: Blueberry leaf; blueberry stem; quercetin; hepatic lipid; rat; functional food

Hepatic Transcriptomic Signature of High-Sucrose Diet in Nonobese Model of Metabolic Syndrome and Prediabetes

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 1723-P
Author(s):  
IRENA MARKOVÁ ◽  
MARTINA HÜTTL ◽  
HANA MALINSKA ◽  
ONDREJ SEDA ◽  
LUDMILA KAZDOVA
Keyword(s):  
Metabolic Syndrome ◽  
Sucrose Diet ◽  
Transcriptomic Signature ◽  
High Sucrose Diet ◽  
High Sucrose

scholarly journals Alternate Day Fasting Combined with a Low Carbohydrate Diet: Effect on Sleep Quality, Duration, Insomnia Severity and Risk of Obstructive Sleep Apnea in Adults with Obesity

Nutrients ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 211
Author(s):  
Faiza Kalam ◽  
Kelsey Gabel ◽  
Sofia Cienfuegos ◽  
Mark Ezpeleta ◽  
Eric Wiseman ◽  
...  
Keyword(s):  
Weight Loss ◽  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Sleep Quality ◽  
Weight Maintenance ◽  
Carbohydrate Diet ◽  
Low Carbohydrate Diet ◽  
Obstructive Sleep ◽  
Low Carbohydrate ◽  
Insomnia Severity

Background: Alternate day fasting combined with a low carbohydrate diet (ADF-LC) is an effective weight loss regimen. Whether the weight loss induced by ADF-LC can improve sleep, remains unknown. Objective: This study examined the effect an ADF-LC diet on sleep quality, duration, insomnia severity and the risk of obstructive sleep apnea. Methods: Adults with obesity (n = 31) participated in ADF (600 kcal “fast day”; ad libitum intake “feast day”) with a low-carbohydrate diet (30% carbohydrates, 35% protein, and 35% fat). The 6-month trial consisted of a 3-month weight loss period followed by a 3-month weight maintenance period. Results: Reductions in body weight (−5 ± 1 kg, p < 0.001) and fat mass (−4 ± 1 kg, p < 0.01) were noted during the weight loss period, and these reductions were sustained during the weight maintenance period. Lean mass and visceral fat remained unchanged. The Pittsburgh Sleep Quality Index (PSQI) score indicated poor sleep quality at baseline (6.4 ± 0.7) with no change by month 3 or 6, versus baseline. ISI score indicated subthreshold insomnia at baseline (8.5 ± 1.0), with no change by month 3 or 6, versus baseline. The percent of subjects with high risk of obstructive sleep apnea at baseline was 45%, with no change by month 3 or 6. Wake time, bedtime, and sleep duration remained unchanged. Conclusion: The ADF-LC diet does not impact sleep quality, duration, insomnia severity or the risk of obstructive sleep apnea in adults with obesity.

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