scholarly journals The development of ketogenesis at birth in the rat

1978 ◽  
Vol 176 (3) ◽  
pp. 759-765 ◽  
Author(s):  
P Ferré ◽  
J P Pégorier ◽  
D H Williamson ◽  
J R Girard
Keyword(s):  
Fatty Acids ◽  
Ketone Bodies ◽  
Liver Glycogen ◽  
Newborn Rat ◽  
Adult Rat ◽  
Rate Limiting Step ◽  
Esterified Fatty Acids ◽  
Major Increase ◽  
Blood Ketone Bodies ◽  
Rate Limiting

In the suckling newborn rat, blood ketone bodies begin to increase slowly 4h after birth and then rise sharply between 12 and 16h, whereas the major increase in plasma non-esterified fatty acids and liver carnitine occurs during the first 2h of life, parallel with the onset of suckling. In the starved newborn rat, which shows no increase in liver carnitine unless it is fed with a carnitine solution, the developmental pattern of the ketogenic capacity (tested by feeding a triacylglycerol emulsion, which increases plasma non-esterified fatty acids by 3-fold) is the same as in the suckling animal. This suggests that the increases in plasma non-esterified fatty acids and liver carnitine seen 2h after birth in the suckling animal are not the predominant factors inducing the switch-on of ketogenesis. Injection of butyrate to starved newborn pups resulted in a pattern of blood ketone bodies which was similar to that found after administration of triacylglycerols, but, at all time points studied, the hyperketonaemia was more pronounced with butyrate. It is suggested that, even if the entry of long-chain fatty acids into the mitochondria is a rate-limiting step, it is not the only factor controlling ketogenesis after birth in the rat. As in the adult rat, there is a reciprocal correlation between the liver glycogen content and the concentration of ketone bodies in the blood.

scholarly journals The metabolism of circulating non-esterified fatty acids by the whole animal, hind-limb muscle and uterus of pregnant ewes

1983 ◽  
Vol 49 (1) ◽  
pp. 129-143 ◽  
Author(s):  
D. W. Pethick ◽  
D. B. Lindsay ◽  
P. J. Barker ◽  
A. J. Northrop
Keyword(s):  
Fatty Acids ◽  
Hind Limb ◽  
Ketone Bodies ◽  
Gravid Uterus ◽  
Limb Muscle ◽  
Entry Rate ◽  
Esterified Fatty Acids ◽  
Arterial Concentration ◽  
Pregnant Sheep ◽  
Hind Limb Muscle

1. The over-all and regional metabolism of non-esterified fatty acids (NEFA) was studied using a combination of isotopic and arteriovenous-difference techniques.2. There was a common linear relationship, whether stearic, palmitic or oleic acids were used as tracer, between the arterial NEFA concentration and the rates of entry and oxidation.3. Assuming that the tracer used reflected the metabolism of all the NEFA, the total entry rate in fed and fasted pregnant ewes was (mean±SE) 0·44±0·02 and 0·55±0·07 mmol/h per kg body-weight respectively. Oxidation of NEFA contributed (mean±SE) 34±5 and 58±7% to the respiratory carbon dioxide in fed and fasted animals, this accounting for (mean±SE) 46±6 and 59±3% of the respective entry rates.4. Hind-limb muscle both utilized and produced NEFA. The mean gross fractional extraction (calculated from isotopic uptake) was (mean±SE) 9±1%. Gross utilization of any NEFA and appearance of 14CO2 across the muscle were linearly related to the arterial concentration of tracer fatty acid, irrespective of whether this was oleate or stearate. The amount of 14CO2 appearing was consistent with (mean±SE) 54±8% of the CO2 produced by the hind-limb being derived from NEFA oxidation.5. Infused NEFA were partly converted to ketone bodies. Uptake and oxidation in the hind-limb of ketones formed in the liver could account for approximately 20% of the 14CO2 apparently produced in muscle from NEFA. Correction for this reduces the proportion of CO2 derived from NEFA to 43%. There was some indication that ketones were also produced from NEFA in the hind-limb.6. NEFA were not a significant energy source for the gravid uterus.7. An over-all view of energy sources for the whole animal and for hind-limb muscle in normal and fasted pregnant sheep was presented.

Persistence of metabolic rhythmicity during fasting and its entrainment by restricted feeding schedules in rats

1998 ◽  
Vol 274 (5) ◽  
pp. R1309-R1316 ◽  
Author(s):  
Carolina Escobar ◽  
Mauricio Díaz-Muñoz ◽  
Fabiola Encinas ◽  
Raúl Aguilar-Roblero
Keyword(s):  
Fatty Acids ◽  
Lipid Metabolism ◽  
Free Fatty Acids ◽  
Ketone Bodies ◽  
Liver Glycogen ◽  
Restricted Feeding ◽  
Feeding Schedule ◽  
Daily Food ◽  
Catabolic State

The presence of a food-entrainable oscillator (FEO) independent from the SCN is now well established, but until now its location and characterization have been elusive. Because its expression requires priming of the animal’s metabolism toward a catabolic state, it is possible that metabolic rhythms may be related to FEO. The present study was designed to determine whether metabolic rhythms persist during fasting and whether such rhythms could be entrained to a restricted feeding schedule. The results indicate persistent rhythms of triacylglycerides, free fatty acids, glucose, and proteins during fasting, whereas ketone bodies and liver glycogen changed their concentration as a function of fasting. Daily food pulses of 2 h entrained the rhythms of triacylglycerides and free fatty acids and restored ketone bodies and liver glycogen to similar levels as controls. Neither glucose nor proteins were affected by the food pulse. These results indicate the relevance of lipid metabolism as a phenomenon associated with the FEO.

Some effects of fasting on rats fed a choline-deficient diet

1960 ◽  
Vol 198 (2) ◽  
pp. 371-374 ◽  
Author(s):  
E. Douglas Rees ◽  
William W. Winternitz ◽  
William F. Lattanzi
Keyword(s):  
Blood Glucose ◽  
Ketone Bodies ◽  
Blood Glucose Concentration ◽  
Liver Glycogen ◽  
Control Group ◽  
Deficient Diet ◽  
Hepatic Fat ◽  
Blood Ketone Bodies ◽  
Deficient Group

The blood ketone body concentrations of fasted and nonfasted rats fed a diet deficient in choline were determined and found to be similar to the concentrations obtained from a control group fed the same diet supplemented with choline. However, the animals on the choline-deficient diet had an 18–20% greater mean liver mass, and this could account for the failure to demonstrate the depressed level of blood ketone bodies which was anticipated on the basis of previous in vitro studies. Other possible explanations of this discrepancy are discussed. Despite a high hepatic fat content, the choline-deficient group had a normal concentration of liver glycogen. The nonfasting blood glucose concentration of the choline-deficient group (91.5 ± 5 mg %) was lower than that of the control group (102 ± 3 mg %). After 24 hours of fasting, the values were 52 ± 3 mg % and 61 ± 5 mg % for the choline-deficient and control group, respectively. The 72-hour fasting values were 43 ± 2 mg %, and 49 ± 2 mg %, respectively. Data showing the effect of diet composition on ketonemia, liver glycogen and blood glucose are presented and are in accord with previous studies.

scholarly journals Changes in the phospholipid catabolism of mitochondria and microsomes during the development of rat liver

1981 ◽  
Vol 200 (3) ◽  
pp. 521-528 ◽  
Author(s):  
J K Pollak ◽  
W Harsas
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Rat Liver ◽  
Acid Formation ◽  
Liver Fatty Acid ◽  
Adult Rat ◽  
Degree Of Unsaturation ◽  
Esterified Fatty Acids

The lipolytic activities of mitochondrial and microsomal fractions (‘microsomes’) isolated from foetal, suckling and adult rat liver were compared. The catabolism of endogenous phospholipids was followed by measuring the loss of phospholipids and the appearance of non-esterified fatty acids and lysophosphatides. The rate of mitochondrial phospholipid catabolism does not change significantly during development, but the rate of lipolysis of microsomal phospholipids increases 3-fold during development. Balance studies showed that, in mitochondria and microsomes of foetal, suckling and adult rat liver, fatty acid formation is greatly in excess of the fatty acids that can be accounted for by measuring phospholipid disappearance and lysophosphatide appearance. The hypothesis that this excess fatty acid formation resulted from the lipolysis of mitochondrial and microsomal triacylglycerols were tested and confirmed by preliminary experiments. Mitochondria and microsomes isolated from all developmental ages investigated had phospholipases with A1 and A2 activities. The degree of unsaturation of the fatty acids derived from the phospholipids of mitochondria did not vary significantly during development.

Exchange of Metabolites in the Leg of Exercising Juvenile Diabetic Subjects

1978 ◽  
Vol 55 (1) ◽  
pp. 73-80 ◽  
Author(s):  
J. Lyngsøe ◽  
J. P. Clausen ◽  
J. Trap-Jensen ◽  
L. Sestoft ◽  
O. Schaffalitzky de Muckadell ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Glucose Uptake ◽  
Ketone Bodies ◽  
Normal Subjects ◽  
Close Correlation ◽  
Juvenile Diabetes ◽  
Control Subjects ◽  
Arterial Blood ◽  
Esterified Fatty Acids ◽  
And Control

1. Exchange of metabolic substrates was studied across the leg at rest and during a bicycle exercise demanding 50% of the maximal oxygen uptake in seven patients with juvenile diabetes and six control subjects. The leg blood flow and the femoral arterial and venous substrate concentrations were measured in the fasting state and, in the diabetic subjects, 24 h after the last administration of insulin. 2. At rest a close correlation was seen in the control subjects between the leg glucose uptake and the arterial insulin concentration. The diabetic subjects, including three patients in whom it could be shown that the insulin concentrations were extremely low, had a resting glucose uptake in the same order of magnitude as the control subjects. The glucose uptake was inversely related to the arterial concentrations of non-esterified fatty acids in both groups. 3. During exercise the glucose uptake increased in both patients and control subjects, but the increase was not related to arterial concentrations of insulin or non-esterified fatty acids. 4. The release of lactate, pyruvate, alanine and glycerol from the leg was not different in diabetic and control subjects neither at rest nor during exercise. 5. The ketonaemia was increased in the diabetic subjects, but the uptake of total ketone bodies was not different in the two groups. No increase in the uptake of total ketone bodies in control and diabetic subjects was found during exercise. The leg uptake of acetoacetate was a function of the substrate load and tended to be higher in diabetic subjects during exercise, when no net uptake of β-hydroxybutyrate was found. 6. The above results suggest that the glucose uptake in human skeletal muscle at rest depends on the concentration of insulin and possibly also of non-esterified fatty acids in arterial blood. In contrast the glucose uptake during exercise is not related to the concentration of insulin or non-esterified fatty acids, which may explain why no differences in this aspect are seen between the leg metabolism of diabetic and normal subjects.

The Relationships between Plasma Substrates and Hormones and the Severity of Injury in 277 Recently Injured Patients

1979 ◽  
Vol 56 (6) ◽  
pp. 563-573 ◽  
Author(s):  
H. B. Stoner ◽  
K. N. Frayn ◽  
R. N. Barton ◽  
C. J. Threlfall ◽  
R. A. Little
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Injury Severity ◽  
Ketone Bodies ◽  
Total Concentration ◽  
Plasma Concentrations ◽  
Severely Injured ◽  
Esterified Fatty Acids ◽  
Severity Of Injury ◽  
Injured Patients

1. The plasma concentrations of glucose, lactate, amino acids, non-esterified fatty acids, glycerol, ketone bodies, ethanol, cortisol and insulin were measured in patients within a few hours of injury and before treatment. The severity of the injuries was assessed by the Injury Severity Score (ISS) method. 2. Plasma lactate and glucose concentrations both rose significantly with increasing ISS. 3. The concentrations of non-esterified fatty acids and glycerol were greater after moderate (ISS 7–12) than after minor (ISS 1–6) injuries. The glycerol concentrations were no higher and the non-esterified fatty acid concentrations were lower after severe (ISS > 12) than after moderate injuries. The concentrations of total ketone bodies tended to follow those of non-esterified fatty acids and there was a highly significant correlation between them. 4. The total concentration of amino acids was not affected by the severity of injury and there were no systematic changes in the concentrations of individual ones. 5. Plasma insulin concentrations were very variable and not related to severity. A weak correlation with the plasma glucose concentration seen after minor and moderate injuries was lost in the severely injured. 6. The plasma cortisol concentration was positively related to ISS up to ISS 12 but negatively so in the severely injured. 7. Factors such as age, sex and time after last meal were investigated. The most important factor modifying the response was intake of ethanol, which reduced the plasma concentrations of glucose, non-esterified fatty acids and alanine and raised that of lactate as well as the [β-hydroxybutyrate]/[acetoacetate] ratio.

Anaerobic batch degradation of solid poultry slaughterhouse waste

2000 ◽  
Vol 41 (3) ◽  
pp. 33-41 ◽  
Author(s):  
E. Salminen ◽  
J. Rintala ◽  
L.Ya. Lokshina ◽  
V.A. Vavilin
Keyword(s):  
Fatty Acids ◽  
Methane Production ◽  
Long Chain Fatty Acids ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Propionate Degradation ◽  
Waste Degradation ◽  
New Generation ◽  
Rate Limiting ◽  
Long Chain

We studied anaerobic batch degradation of solid poultry slaughterhouse wastes with different initial waste and inoculum concentrations and waste-to-inoculum ratios and simulated the dynamics of the process with a new generation <METHANE> model. Our modelling results suggest that inhibited propionate degradation by long-chain fatty acids (LCFA) and inhibited hydrolysis by a high propionate concentration constituted the rate-limiting step in the waste degradation. Palmitate was the most abundant LCFA in the assays. Within 27 days of incubation, up to 0.55 to 0.67 m3 of methane (STP)/kg VS added was produced under the studied conditions. Lower waste-to-inoculum ratios exhibited a faster onset and rate of specific methane production. In all the assays, ammonification occurred within 3 to 6 days and accounted for 50 to 60% of total nitrogen.

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