scholarly journals Relationship between hepatic fatty acid oxidation and gluconeogenesis in the fasting neonatal pig

1993 ◽  
Vol 70 (1) ◽  
pp. 81-91 ◽  
Author(s):  
Allan J. Lepine ◽  
Malcolm Watford ◽  
R. Dean BOYD ◽  
Deborah A. Ross ◽  
Dana M. Whitehead
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Oxidative Capacity ◽  
Synthesis Rate ◽  
Acid Oxidation ◽  
Limiting Factor ◽  
Glucose Synthesis ◽  
Newborn Pigs ◽  
Hepatic Fatty Acid Oxidation

Hepatocytes were isolated from sixteen fasting neonatal pigs and used in two experiments: (1) to determine the effect of various factors on the ability for hepatic oxidation of fatty acids and (2) to clarify the relationship between fatty acid oxidation and glucose synthesis. In Expt 1, newborn pigs were either fasted from birth for 24 h or allowed to suck ad lib. for 3 d followed by a 24 h fast. In the presence of pyruvate, oxidation of octanoate (2 mM) was about 30-fold greater than oleate (1 mM) regardless of age, but glucose synthesis was not enhanced beyond that observed for pyruvate alone. Inclusion of carnitine (1 mM), glucagon (100 nM) or dibutryl cAMP (50 μM) in the incubation media did not stimulate either fatty acid oxidation (octanoate or oleate) or glucose synthesis. Extending the period of fasting to 48 h (Expt 2) failed to enhance the fatty acid oxidative capacity or glucose synthesis rate. Likewise, the redox potential of the giuconeogenic substrate (lactate v. pyruvate) did not influence glucose synthesis regardless of the oxidative capacity exhibited for fatty acids. These data indicate that fatty acid oxidative capacity is not the first limiting factor to full expression of gluconeogenesis in hepatocytes isolated from fasted newborn pigs.

Meal composition affects postprandial fatty acid oxidation

1993 ◽  
Vol 264 (6) ◽  
pp. R1065-R1070 ◽  
Author(s):  
D. M. Surina ◽  
W. Langhans ◽  
R. Pauli ◽  
C. Wenk
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Nutrient Utilization ◽  
Whole Body ◽  
Acid Oxidation ◽  
Plasma Ffa ◽  
Hepatic Fatty Acid Oxidation ◽  
Beta Hydroxybutyrate ◽  
Chain Fatty Acids

The influence of macronutrient content of a meal on postprandial fatty acid oxidation was investigated in 13 Caucasian males after consumption of a high-fat (HF) breakfast (33% carbohydrate, 52% fat, 15% protein) and after an equicaloric high-carbohydrate (HC) breakfast (78% carbohydrate, 6% fat, 15% protein). The HF breakfast contained short- and medium-chain fatty acids, as well as long-chain fatty acids. Respiratory quotient (RQ) and plasma beta-hydroxybutyrate (BHB) were measured during the 3 h after the meal as indicators of whole body substrate oxidation and hepatic fatty acid oxidation, respectively. Plasma levels of free fatty acids (FFA), triglycerides, glucose, insulin, and lactate were also determined because of their relationship to nutrient utilization. RQ was significantly lower and plasma BHB was higher after the HF breakfast than after the HC breakfast, implying that more fat is burned in general and specifically in the liver after an HF meal. As expected, plasma FFA and triglycerides were higher after the HF meal, and insulin and lactate were higher after the HC meal. In sum, oxidation of ingested fat occurred in response to a single HF meal.

scholarly journals Interactions in vivo between oxidation of non-esterified fatty acids and gluconeogenesis in the newborn rat

1979 ◽  
Vol 182 (2) ◽  
pp. 593-598 ◽  
Author(s):  
P Ferré ◽  
J P Pégorier ◽  
D H Williamson ◽  
J Girard
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Pyruvate Carboxylase ◽  
Acid Oxidation ◽  
Newborn Rat ◽  
Esterified Fatty Acids ◽  
Metabolic Interactions ◽  
Hepatic Fatty Acid Oxidation

Metabolic interactions between fatty acid oxidation and gluconeogenesis were investigated in vivo in 16h-old newborn rats under various nutritional states. As the newborn rat has no white adipose tissue, starvation from birth induces a low rate of hepatic fatty acid oxidation. Hepatic gluconeogenesis in inhibited in the starved newborn rat when compared with the suckling rat, which receives fatty acids through the milk, at the steps catalysed by pyruvate carboxylase and glyceraldehyde 3-phosphate dehydrogenase. These inhibitions are rapidly reversed by triacylglycerol feeding. Inhibition of fatty acid oxidation by pent-4-enoate in the suckling animal mimics the effect of starvation on the pattern of hepatic gluconeogenic metabolites. It is concluded that, in the newborn rat in vivo, hepatic fatty acids oxidation can increase the gluconeogenic flux by providing the acetyl-CoA necessary for the reaction catalysed by pyruvate carboxylase and the reducing equivalents (NADH) to displace the reversible reaction catalysed by glyceraldehyde 3-phosphate dehydrogenase in the direction of gluconeogenesis.

Metabolic development in the liver and the implications of the n-3 fatty acid supply

2012 ◽  
Vol 302 (2) ◽  
pp. G250-G259 ◽  
Author(s):  
Elizabeth M. Novak ◽  
Bernd O. Keller ◽  
Sheila M. Innis
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Maternal Diet ◽  
Neonatal Rat ◽  
Metabolic Adaptation ◽  
Acid Oxidation ◽  
Flight Mass Spectrometry ◽  
2D Gel ◽  
Hepatic Fatty Acid Oxidation

The n-3 fatty acids contribute to regulation of hepatic fatty acid oxidation and synthesis in adults and accumulate in fetal and infant liver in variable amounts depending on the maternal diet fat composition. Using 2D gel proteomics and matrix-assisted laser desorption/ionization time of flight mass spectrometry, we recently identified altered abundance of proteins associated with glucose and amino acid metabolism in neonatal rat liver with increased n-3 fatty acids. Here, we extend studies on n-3 fatty acids in hepatic metabolic development to targeted gene and metabolite analyses and map the results into metabolic pathways to consider the role of n-3 fatty acids in glucose, fatty acid, and amino metabolism. Feeding rats 1.5% compared with <0.1% energy 18:3n-3 during gestation led to higher 20:5n-3 and 22:6n-3 in 3-day-old offspring liver, higher serine hydroxymethyltransferase, carnitine palmitoyl transferase, and acyl CoA oxidase and lower pyruvate kinase and stearoyl CoA desaturase gene expression, with higher cholesterol, NADPH and glutathione, and lower glycine ( P < 0.05). Integration of the results suggests that the n-3 fatty acids may be important in facilitating hepatic metabolic adaptation from in utero nutrition to the postnatal high-fat milk diet, by increasing fatty acid oxidation and directing glucose and amino acids to anabolic pathways.

scholarly journals Fatty acid oxidation by liver and muscle preparations of exhaustively exercised rats

1982 ◽  
Vol 208 (2) ◽  
pp. 419-424 ◽  
Author(s):  
H A Barakat ◽  
G J Kasperek ◽  
G L Dohm ◽  
E B Tapscott ◽  
R D Snider
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Oxidative Capacity ◽  
Normal Function ◽  
Acid Oxidation ◽  
Beta Oxidation ◽  
Beta Hydroxybutyrate

The influence of exhaustive exercise on the capacity of liver and muscle of rats to oxidize fatty acids was investigated in vitro. The rate of oxidation of fatty acids by liver preparations was significantly elevated as a result of exhaustion. Concurrently, the concentrations of beta-hydroxybutyrate were elevated in the plasma of the exhausted rats, suggesting that oxidation of fatty acids was also elevated in vivo. These findings are analogous to the findings of increased oxidation of fatty acids that results from training. In muscle, oxidation of palmitate, palmitoylcarnitine and beta-hydroxybutyrate by homogenates and isolated mitochondria was depressed with exercise. Despite the decrease in the oxidative capacity of the muscle preparations, the activities of several enzymes of beta-oxidation were either increased or unchanged as a result of exercise, suggesting that the depression in fatty acid oxidation may not be related to alterations in the process of beta-oxidation. Further studies showed that oxidation of [2-(14)C]pyruvate by muscle was depressed, whereas oxidation of [1-(14)C]pyruvate was not changed as a result of exercise. These results suggest that the decrease in fatty acid oxidation may be related to aberrations in the oxidation of acetyl-CoA. The changes in fatty acid oxidation that were observed, which are at variance with what is reported to occur with training, may have resulted from increased fragility of muscle mitochondria as a result of exercise. This increased fragility may render the mitochondria more susceptible to experimental manipulations in vitro and a subsequent loss of normal function.

scholarly journals Metabolic fate of non-esterified fatty acids in isolated hepatocytes from newborn and young pigs. Evidence for a limited capacity for oxidation and increased capacity for esterification

1983 ◽  
Vol 212 (1) ◽  
pp. 93-97 ◽  
Author(s):  
J P Pégorier ◽  
P H Duée ◽  
J Girard ◽  
J Peret
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Fatty Acid Uptake ◽  
Isolated Hepatocytes ◽  
Acid Oxidation ◽  
Acid Uptake ◽  
Limited Capacity ◽  
Newborn Pigs ◽  
Species Specific

In hepatocytes isolated from 48 h-old starved of suckling newborn pigs or from 15-day-old starved piglets, the rate of ketogenesis from oleate or from octanoate is very low. This is not due to an inappropriate fatty acid uptake by the isolated liver cells, but results from a limited capacity for fatty acid oxidation. Some 80-95% of oleate taken up is converted into esterified fats, whatever the age or the nutritional conditions. Three lines of indirect evidences suggest that fatty acid oxidation is not controlled primarily by malonyl-CoA concentration in newborn pig liver. Firstly, the addition of glucagon does not increase fatty acid oxidation or ketogenesis. Secondly, the rate of lipogenesis is very low in isolated hepatocytes from newborn pigs. Thirdly, the rates of oxidation and ketogenesis from octanoate are also decreased in isolated hepatocytes from newborn and young piglets. The huge rate of esterification of fatty acids in the liver of the newborn pigs probably represents a species-specific difference in intrahepatic fatty acid metabolism.

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