scholarly journals The effect of starvation and refeeding on lipogenic enzymes in mammary glands and livers of lactating rats

1983 ◽  
Vol 216 (2) ◽  
pp. 515-518 ◽  
Author(s):  
M R Grigor ◽  
K R Gain
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Serum Insulin ◽  
Mammary Glands ◽  
High Carbohydrate Diet ◽  
Milk Secretion ◽  
Lipogenic Enzymes ◽  
Carbohydrate Diet ◽  
High Carbohydrate ◽  
Glucose 6 Phosphate Dehydrogenase

Lactating rats were starved for 48 h and refed a high-carbohydrate diet for a further 48 h. Starvation stops milk secretion, which resumes shortly after refeeding. Three lipogenic enzymes, fatty acid synthase, glucose 6-phosphate dehydrogenase (EC 1.1.1.49) and ‘malic’ enzyme (EC 1.1.1.40) all decrease in the mammary gland during starvation and are restored to the pre-starvation levels 48 h after refeeding. The same enzymes in liver also decrease during starvation, but increase to values significantly higher than those for the normal fed rats after refeeding the high-carbohydrate diet. For the fatty acid synthase these values were four times the pre-starvation values. Serum insulin and prolactin concentrations also increased upon refeeding the high-carbohydrate diet.

scholarly journals Regulation of lipogenic capacity in lactating rats

1982 ◽  
Vol 208 (3) ◽  
pp. 611-618 ◽  
Author(s):  
M R Grigor ◽  
A Geursen ◽  
M J Sneyd ◽  
S M Warren
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Malic Enzyme ◽  
Fatty Acid Synthase ◽  
Specific Activity ◽  
Mammary Glands ◽  
Lipogenic Enzymes ◽  
Pregnancy And Lactation ◽  
Specific Activities

1. The rate of mammary-gland lipogenesis measured in vivo from 3H2O was suppressed after decreasing the milk demand by decreasing the number of pups from ten to two or three, as well as by giving diets containing lipid [Grigor & Warren (1980) Biochem. J. 188, 61-65]. 2. The specific activities of the lipogenic enzymes fatty acid synthase, glucose 6-phosphate dehydrogenase and ‘malic’ enzyme increased between 6- and 10-fold in the mammary gland and between 2- and 3-fold in the livers during the first 10 days of lactation. The increases in specific activity coupled with the doubling of liver mass which occurred during pregnancy and lactation resulted in considerable differences in total liver activities when compared with virgin animals. 3. Although consumption of a diet containing 20% peanut oil suppressed the activities of the three lipogenic enzymes in the livers, only the ‘malic’ enzyme was affected in the mammary glands. 4. In contrast, decreased milk demand did not affect the specific activities of any of the liver enzymes, whereas it resulted in suppression of all three lipogenic enzymes of the mammary glands. There was no effect on either the cytoplasmic malate dehydrogenase or the lactate dehydrogenase of the mammary gland. 5. In all the experiments performed, the activity of the fatty acid synthase correlated with the amount of material precipitated by the rabbit antibody raised against rat fatty acid synthase.

scholarly journals A low-protein, high-carbohydrate diet increases de novo fatty acid synthesis from glycerol and glycerokinase content in the liver of growing rats

2013 ◽  
Vol 33 (6) ◽  
pp. 494-502 ◽  
Author(s):  
Andreza Lúcia Menezes ◽  
Mayara Peron Pereira ◽  
Samyra Lopes Buzelle ◽  
Maísa Pavani dos Santos ◽  
Suélem Aparecida de França ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Acid Synthesis ◽  
High Carbohydrate Diet ◽  
Carbohydrate Diet ◽  
High Carbohydrate ◽  
Growing Rats ◽  
Low Protein

Low-protein, high-carbohydrate diet increases glucose uptake and fatty acid synthesis in brown adipose tissue of rats

Nutrition ◽  
2014 ◽  
Vol 30 (4) ◽  
pp. 473-480 ◽  
Author(s):  
Suélem Aparecida de França ◽  
Maísa Pavani dos Santos ◽  
Roger Vinícius Nunes Queiroz da Costa ◽  
Mendalli Froelich ◽  
Samyra Lopes Buzelle ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
High Carbohydrate Diet ◽  
Carbohydrate Diet ◽  
High Carbohydrate ◽  
Low Protein ◽  
Brown Adipose

scholarly journals Liver Fatty Acid Composition and Inflammation in Mice Fed with High-Carbohydrate Diet or High-Fat Diet

Nutrients ◽  
2016 ◽  
Vol 8 (11) ◽  
pp. 682 ◽  
Author(s):  
Lorena da Silva-Santi ◽  
Marina Antunes ◽  
Silvana Caparroz-Assef ◽  
Fabiana Carbonera ◽  
Laureane Masi ◽  
...  
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
High Fat Diet ◽  
High Carbohydrate Diet ◽  
Liver Fatty Acid ◽  
High Fat ◽  
Carbohydrate Diet ◽  
High Carbohydrate

The Effects of Catecholamines, Glucagon, and Diet on Enzyme Activities in Brown Fat and Liver of the Rat

1974 ◽  
Vol 52 (9) ◽  
pp. 739-743 ◽  
Author(s):  
Peter Hahn ◽  
Lorne T. Kirby
Keyword(s):  
Body Weight ◽  
Fatty Acid ◽  
Malic Enzyme ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Fatty Acid Synthetase ◽  
High Carbohydrate Diet ◽  
Brown Fat ◽  
Carbohydrate Diet ◽  
High Carbohydrate ◽  
Cleavage Enzyme

The effects of a high carbohydrate diet fed to young rats for 24–48 h on phosphoenolpyruvate carboxykinase, malic enzyme, citrate-cleavage enzyme, and fatty acid synthetase could be overcome by injecting the animals with glucagon (1 mg/100 g body weight) or norepinephrine (20 μg/100 g body weight) four times a day. The same effect was achieved with 50 mg ephedrine added to the 24 h diet. The catecholamines were more effective in brown fat, whereas glucagon seemed somewhat more effective in the liver.

scholarly journals Studies on the biosynthesis of hepatic pyruvate kinase and its correlation with enhanced hepatic lipogenesis in meal-trained rats

1979 ◽  
Vol 182 (2) ◽  
pp. 383-397 ◽  
Author(s):  
T J Hopkirk ◽  
D P Bloxham
Keyword(s):  
Fatty Acid ◽  
Pyruvate Kinase ◽  
Fatty Acid Synthesis ◽  
Specific Activity ◽  
Acid Synthesis ◽  
High Carbohydrate Diet ◽  
Hill Coefficient ◽  
Carbohydrate Diet ◽  
High Carbohydrate ◽  
Maximum Activation

Metabolic and enzymic changes were measured in meal-trained rats fed on high-carbohydrate diet. Rates of hepatic fatty acid synthesis are probably greater than rates of gluconeogenesis throughout the 24 h day provided that animals are fed. The daily enhancement of fatty acid synthesis on meal feeding coincided with the maximum activation of hepatic pyruvate kinase. Maximum activation of this enzyme was reflected in increased total catalytic activity (Vmax.), increased activity at 0.5 MM-phosphoenolpyruvate (V0.5), decreased Vmax./V0.5 ratio and a decrease in co-operativity of phosphoenolpyruvate binding as measured by the Hill coefficient (h). The latter changes are consistent with a decrease in enzyme phosphorylation during activation of the enzyme. To estimate changes in enzyme protein, quantitative enzyme precipitation with rabbit antisera was used. Giving a high-carbohydrate diet to meal-trained animals induced enzyme synthesis within a few hours. Adaptations in diet that enhanced fatty acid synthesis (chow to high carbohydrate; starved to high carbohydrate) led to an increased steady-state concentration of pyruvate kinase protein. An approximate estimate of the half-life of hepatic pyruvate kinase was 56 h. Whenever pyruvate kinase specific activity was measured in liver tissue extracts it was always considerably less (20–100 mumol/min per mg of protein, depending on dietary status) than the specific activity of pure pyruvate kinase (200 mumol/min per mg of protein). Antigenically active, catalytically inactive protein was removed during enzyme purification from cytosol at the stage of (NH4)2SO4 fractionation. The fraction precipitated by 30–45%-satd. (NH4)2SO4 was enzymically active, antigenically reacting protein was identified in the remaining (NH4)2SO4 fractions (0–30%- and 45–85%-satd.) and this contained no enzyme activity. These may correspond to inactive proteolytic fragments of pyruvate kinase. The rate-determining step in adjusting enzyme concentration seems to be proteolysis.

scholarly journals The effect of carbohydrate and fat variation in euenergetic diets on postabsorptive free fatty acid release

2002 ◽  
Vol 87 (6) ◽  
pp. 555-559 ◽  
Author(s):  
Peter H. Bisschop ◽  
Mariëtte T. Ackermans ◽  
Erik Endert ◽  
An F. C. Ruiter ◽  
Alfred J. Meijer ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
High Fat Diet ◽  
Fat Oxidation ◽  
High Carbohydrate Diet ◽  
The Other ◽  
High Fat ◽  
Carbohydrate Diet ◽  
High Carbohydrate ◽  
And Control

Diet composition and energy content modulate free fatty acid (FFA) release. The aim of this study was to evaluate the dose–response effects of euenergetic variations in dietary carbohydrate and fat content on postabsorptive FFA release. The rate of appearance (Ra) of palmitate was measured by infusion of [2,2-2H2]palmitate after an overnight fast in six healthy men on three separate occasions, i.e. after 7 d on euenergetic control, high-carbohydrate and high-fat diets. The protein content and composition was identical for each diet. Postabsorptive plasma fatty acid concentrations were not different between the high-carbohydrate and control diets (0·36 (SE 0·07) V. 0·43 (se 0·04) mmol/l), but were increased after the high-fat diet (0·75 (se 0·09) mmol/l, (P<0·01 compared with the other diets). Ra palmitate was not different between the high-carbohydrate and control diets (1·36 (se 0·20) v. 1·47 (se 0·15) μmol/kg per min). However, Ra palmitate was increased to 2·36 (se 0·26) μmol/kg per min after the high-fat diet (P<0·01 compared with the other diets). The fatty acid flux and whole-body fat oxidation were not affected by the high-carbohydrate diet compared with the control diet, but were increased by 67 and 47 % respectively, on the high-fat diet (P<0·01 compared with the other diets). A euenergetic high-fat diet results in increased postabsorptive FFA release and fat oxidation, whereas a euenergetic high-carbohydrate diet does not affect these variables of fat metabolism.

Nutritional Regulation of the Activities of Lipogenic Enzymes of Rat Liver and Brown Adipose Tissue

1996 ◽  
Vol 51 (11-12) ◽  
pp. 859-869 ◽  
Author(s):  
Meinrad Boll ◽  
Lutz W. D Weber ◽  
Andreas Stampfl
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Enzyme Activities ◽  
High Carbohydrate Diet ◽  
Lipogenic Enzymes ◽  
Carbohydrate Diet ◽  
Interscapular Brown Adipose Tissue ◽  
High Carbohydrate ◽  
Brown Adipose ◽  
Specific Activities

Abstract Nutrition-induced effects on the activity of enzymes of lipogenesis, fatty acid synthase (FAS; EC 2.3.1.85). ATP citrate lyase (ACL; 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 dehy­ drogenase (PGDH; EC 1.1.1.44) were investigated in liver and interscapular brown adipose tissue (BAT) of rats. The lipogenic enzymes could be grouped into two categories according to their response to dietary manipulations; FAS and ACL. both key enzymes of lipogenesis, responded fast and strongly to dietary manipulations. ME, G6PDH and PDGH, enzymes which also contribute to metabolic pathways other than lipogenesis, responded in a more sustained and less pronounced fashion. Feed deprivation caused the specific activities of lipogenic enzymes to decline several-fold. Refeeding of previously fasted (up to 3 days) animals increased the activities dramatically (10-to 25-fold) to far above pre-fasting levels (“overshoot”). Repetition of the fasting/refeeding regimen increasingly impaired the ability of both tissues to synthesize overshooting enzyme activities in the subsequent refeeding period. The fasting-induced decline of the activities was prevented when sugars were provided to the animals via drinking water. The sugars displayed different effectivities; sucrose= glucose> fructose> maltose » lactose. Sugars as the sole nutrient after fasting were also able to induce overshooting enzyme activities. Again, activities of FAS and ACL responded in a more pronounced fashion than the other three enzymes. Transition from feeding one diet to feeding a new diet of different composition led to adaptation of the lipogenic enzyme activities to levels characteristic for the new diet. Replacing a low-carbohydrate with a high-carbohydrate diet proceeded with major alterations of enzyme activities. This process of attaining a new level took up to 20 days and involved pronounced oscillations of the specific activities. In contrast, when a high-carbohydrate diet was replaced with another diet, particular one high in fat, transition to new enzyme activities was completed within 2 -3 days and proceeded without oscillations. All dietary manipulations caused more pronounced responses in young (35d-old) than in adult (180d-old) animals.

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