scholarly journals Studies on lipogenesis in vivo. Lipogenesis during extended periods of re-feeding after starvation

1968 ◽  
Vol 106 (2) ◽  
pp. 345-353 ◽  
Author(s):  
G. R. Jansen ◽  
M. E. Zanetti ◽  
C. F. Hutchison
Keyword(s):  
Fatty Acids ◽  
Corn Oil ◽  
Fat Content ◽  
Limited Access ◽  
Epididymal Fat ◽  
Extrahepatic Tissues ◽  
Ad Libitum ◽  
Access To Food ◽  
Fat Pads

1. Lipogenesis was studied in mice re-fed for up to 21 days after starvation. At appropriate times [U−14]glucose was given by stomach tube and incorporation of 14C into various lipid fractions measured. 2. In mice starved for 48hr. and then re-fed for 4 days with a diet containing 1% of corn oil, incorporation of 14C from [U−14C]glucose into liver fatty acids and cholesterol was respectively threefold and eightfold higher than in controls fed ad libitum. The percentages by weight of fatty acids and cholesterol in the liver also increased and reached peaks after 7 days. Both the radioactivity and weights of the fractions returned to control values after 10–14 days' re-feeding. These changes could be diminished by re-feeding the mice with a diet containing 20% of corn oil. Incorporation of 14C from [U−14C]glucose into extrahepatic fatty acids (excluding those of the epididymal fat pads) was not elevated during re-feeding with a diet containing either 1% or 20% of corn oil. However, incorporation of 14C from [U−14C]glucose into the fatty acids of the epididymal fat pads was increased in mice re-fed with either diet, as compared with non-starved controls. 3. Lipogenesis was also studied in mice alternately fed and starved. Mice given a diet containing 1% of corn oil for 6hr./day for 4 weeks lost weight initially and never attained the weight or carcass fat content of controls fed ad libitum. Incorporation of 14C from dietary [U−14C]-glucose into the fatty acids of the epididymal fat pads was elevated threefold in the mice allowed limited access to food, although the incorporation into the remainder of the extrahepatic fatty acids was not different from that found for controls. Mice given a diet containing 20% of corn oil for 6hr./day adapted to the limited feeding regimen quicker and in 4 weeks did attain the weight and carcass fat content of controls. Incorporation of 14C from [U−14C]glucose into the fatty acids of the epididymal fat pads and the remainder of the extrahepatic fatty acids was respectively fivefold and threefold higher than in controls fed ad libitum. 4. The elevation in liver lipogenesis during re-feeding was greatest on a diet containing 1% of corn oil, whereas in extrahepatic tissues the increase in lipogenesis was greater when the mice were re-fed or were allowed limited access to a diet containing 20% of corn oil. These results suggest that the causes of the increased rate of incorporation of 14C from [U−14C]glucose into fatty acids during re-feeding may be different in liver from that in extrahepatic tissues.

The inhibitory effects of some adenosine nucleolipids on the lipolysis in rat epididymal fat pads in vitro

1979 ◽  
Vol 44 (5) ◽  
pp. 1651-1656 ◽  
Author(s):  
Sixtus Hynie ◽  
Jiří Smrt
Keyword(s):  
Fatty Acids ◽  
Cyclic Amp ◽  
Dibutyryl Cyclic Amp ◽  
Inhibitory Effects ◽  
Epididymal Fat ◽  
Fat Pads

3'-Oleolyl-2,3-dihydroxypropyl-AMP, 3'-stearoyl-2,3-dihydroxypropyl-AMP, octadecyl-AMP and palmitamidoethyl-AMP inhibited in comparison with adenosine or fatty acids much stronger the lipolysis in rat epididymal fat pads in vitro stimulated by isoproterenol, theophylline and dibutyryl cyclic AMP. The inhibition of the effects of the two latter drugs suggest that the described effect is caused not only by the inhibition of the cyclic AMP production but also by the inhibition of its effect on the following steps in process of lipolysis.

Effect of calorie restriction on in vivo glucose metabolism by individual tissues in rats

1999 ◽  
Vol 276 (4) ◽  
pp. E728-E738 ◽  
Author(s):  
Thomas J. Wetter ◽  
Annie C. Gazdag ◽  
David J. Dean ◽  
Gregory D. Cartee
Keyword(s):  
Glucose Metabolism ◽  
Glucose Uptake ◽  
Calorie Restriction ◽  
The Other ◽  
Index Formula ◽  
Tracer Technique ◽  
Ad Libitum ◽  
White Fat ◽  
Fat Pads

We evaluated the effects of 8 mo of calorie restriction [CR: 60% of ad libitum (AL) food intake] on glucose uptake by 14 tissues in unanesthetized, adult (12 mo) F344×BN rats. Glucose metabolism was assessed by the 2-[3H]deoxyglucose tracer technique at 1500 or 2100. Despite an ∼60% decline in insulinemia with CR, plasma 2-[3H]deoxyglucose clearance for CR was greater than for AL at both times. A small, CR-related decrease in glucose metabolic index ([Formula: see text]) occurred only at 1500 in the spleen and heart, and this decrease was reversed at 2100. In some tissues (cerebellum, lung, kidney, soleus, and diaphragm),[Formula: see text] was unaffected by diet, regardless of time. In the other tissues (brown fat, 3 white fat pads, epitrochlearis, plantaris, and gastrocnemius),[Formula: see text] was higher or tended to be higher for CR vs. AL at one or both times. These findings indicate that 8 mo of CR did not cause a continuous reduction in in vivo glucose uptake by any tissue studied, and, in several insulin-sensitive tissues, glucose uptake was at times greater for CR vs. AL rats.

Lipid peroxidation as one mode of action in ochratoxin A toxicity in rats and chicks

1997 ◽  
Vol 77 (2) ◽  
pp. 287-292 ◽  
Author(s):  
Dirk Hoehler ◽  
Ronald R. Marquardt ◽  
Andrew A.F. Rohlich
Keyword(s):  
Lipid Peroxidation ◽  
Fatty Acids ◽  
Ochratoxin A ◽  
Sunflower Oil ◽  
Mode Of Action ◽  
Unsaturated Fatty Acids ◽  
Corn Oil ◽  
Iron Catalyst ◽  
Different Tissues

The objective of this study was to determine whether lipid peroxidation is one mode of action in ochratoxin A (OA) toxicity in vivo. Lipid peroxidation was monitored by analyzing malondialdehyde (MDA) in different tissues by HPLC. A refinement study on the MDA assay was carried out, which showed the importance of the addition of an iron catalyst for the decomposition of hydroperoxides to yield a maximum amount of MDA from a given sample. The rat experiment was designed in a 2 × 2 factorial arrangement using 4 × 6 animals. The four different diets were fed for 21 d and contained either 1% corn oil and 9% tallow (Diets I and III) or 10% corn oil (Diets II and IV); in groups III and IV, 5 mg OA were added per kilogram of diet. For the chick experiment 4 × 8 Leghorn cockerels received diets for 14 d with no added sunflower oil (Diets I and III), whereas the diets of groups II and IV were supplemented with 2.5% sunflower oil. In groups III and IV, 2.5 mg OA were added per kilogram of diet. In both experiments OA decreased the performance of the animals significantly. In the rat experiment an increased lipid peroxidation due to a higher dietary level of unsaturated fatty acids could be obtained, when muscle samples were oxidatively stressed with Fe3+ and ascorbic acid. In the chick experiment there were very clear effects of the dietary treatment on the MDA concentrations of different tissues, as both a higher supply with unsaturated fatty acids and OA increased most of the MDA values significantly. These data suggest that lipid peroxides are formed in vivo by OA, but the effects may vary considerably from species to species, and may also be influenced by other factors. Key words: Ochratoxin A, lipid peroxidation, malondialdehyde, rat, chick

In Vivo Incorporation of Labeled Acetate into Liver and Serum Lipids of Rate on Different Dietary Regimens

1972 ◽  
Vol 50 (5) ◽  
pp. 557-562 ◽  
Author(s):  
B. Serdarevich ◽  
K. K. Carroll
Keyword(s):  
Fatty Acids ◽  
Serum Lipids ◽  
Corn Oil ◽  
In Vitro Studies ◽  
Liver Cholesterol ◽  
Suckling Rats

Incorporation of intravenously injected 1-14C-acetate into lipids of liver and serum was studied in suckling rats and in rats fed commercial or semisynthetic diets containing no added fat, 15% butter, or 15% corn oil. Incorporation into liver cholesterol was higher on commercial than on semisynthetic diets and was stimulated by addition of corn oil to either diet. Incorporation into fatty acids did not parallel incorporation into cholesterol in the different dietary groups. Serum lipids tended to show a pattern of labeling similar to that of liver. Suckling rats showed low incorporation into both cholesterol and fatty acids. In general, these results correspond to the findings of earlier in vitro studies.

scholarly journals Inactivation of rat adipocyte pyruvate dehydrogenase by palmitate. Protection against this effect by insulin in the presence of glucose

1979 ◽  
Vol 184 (1) ◽  
pp. 59-62 ◽  
Author(s):  
S R Sooranna ◽  
E D Saggerson
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Dehydrogenase Activity ◽  
Pyruvate Dehydrogenase ◽  
Protective Action ◽  
Active Form ◽  
Rat Plasma ◽  
Epididymal Fat ◽  
Fat Pads

1. Adipocytes from rat epididymal fat-pads were incubated for 30 min with 5 mM-glucose and concentrations of lactate, pyruvate and amino acids typical of those found in rat plasma. 2. PDHa (active form of pyruvate dehydrogenase) activity was significantly increased after incubation of the cells with insulin (200 micro-i.u./ml), and decreased by incubation with palmitate (0.5–2 mM). 3. In the presence of insulin, palmitate did not decrease PDHa activity. 4. Dichloroacetate (1 mM) increased PDHa activity in the absence of palmitate to the same extent as did insulin. In the presence of dichloroacetate but the absence of insulin, palmitate decreased PDHa activity. In the presence of dichloroacetate and insulin, palmitate again did not decrease PDHa activity. 5. It is concluded that, in the presence of glucose, insulin has a strong protective action against inactivation of adipocyte PDHa by fatty acids.

scholarly journals The Dietary Total-Fat Content Affects the In Vivo Circulating C15:0 and C17:0 Fatty Acid Levels Independently

Nutrients ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1646 ◽  
Author(s):  
Benjamin Jenkins ◽  
Manar Aoun ◽  
Christine Feillet-Coudray ◽  
Charles Coudray ◽  
Martin Ronis ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fat Content ◽  
Dietary Biomarkers ◽  
Dietary Fatty Acid Composition ◽  
Fat Consumption ◽  
Total Fat ◽  
Complex Influence ◽  
Fatty Acid Compositions

Pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0) have been described as dietary biomarkers of dairy-fat consumption, with varying degrees of reliability between studies. It remains unclear how the total amount of dietary fat, representing one of the main confounding factors in these biomarker investigations, affects C15:0 and C17:0 circulating concentrations independent of their relative intake. Additionally, it is not clear how changes in the dietary total-fat affects other fatty acids in circulation. Through two dietary studies with different total-fat levels but maintaining identical fatty acid compositions, we were able to see how the dietary total-fat affects the fatty acids in circulation. We saw that there was a statistically significant, proportionate, and robust decrease in the endogenous C15:0 levels with an increase in dietary total-fat. However, there was no significant change in the circulating C17:0 concentrations as the total-fat increased. To conclude, the dietary total-fat content and fat-type have a very complex influence on the relative compositions of circulating fatty acids, which are independent of the actual dietary fatty acid composition. Knowing how to manipulate circulating C15:0 and C17:0 concentrations is far-reaching in nutritional/pathological research as they highlight a dietary route to attenuate the development of metabolic disease (both by reducing risk and improving prognosis).

THE STIMULATING EFFECTS OF ADRENALINE AND ANTERIOR PITUITARY HORMONES ON THE RELEASE OF FREE FATTY ACIDS FROM ADIPOSE TISSUE

1962 ◽  
Vol 25 (2) ◽  
pp. 189-198 ◽  
Author(s):  
R. M. BUCKLE
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Pituitary Hormones ◽  
Thyroid Stimulating Hormone ◽  
Adrenocorticotrophic Hormone ◽  
Fat Pads

SUMMARY The quantity of free fatty acids (FFA) released from rat epididymal fat pads in vitro and their concentration within the tissue were determined. The addition of adrenaline, adrenocorticotrophic hormone (ACTH), thyroid stimulating hormone (TSH) and growth hormone (GH) each increased the release of FFA, and their respective minimum effective concentrations were 0·125, 0·004, 0·5 and 1·25 μg./ml. of medium. In every case, the increased release of FFA was associated with a rise in the quantity present within the pads, and the amount released closely paralleled their concentration within the tissue. It is suggested that the stimulatory effect of all four hormones on the release of FFA from adipose tissue is largely a manifestation of their activity of increasing the concentration of FFA within the cells, and this they do by facilitating the net conversion of storage triglyceride to fatty acid. The significance of the relative activities of the hormones in vitro is discussed and compared with their fatty acid mobilizing effects in vivo.

Comparison of the effects of dietary n−3 and n−6 polyunsaturated fatty acids on very-low-density lipoprotein secretion when delivered to hepatocytes in chylomicron remnants

2001 ◽  
Vol 357 (2) ◽  
pp. 481-487 ◽  
Author(s):  
Xiaozhong ZHENG ◽  
Michael AVELLA ◽  
Kathleen M. BOTHAM
Keyword(s):  
Fatty Acids ◽  
Polyunsaturated Fatty Acids ◽  
Fish Oil ◽  
Corn Oil ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Chylomicron Remnants

The effects of chylomicron remnants enriched in n-3 or n-6 polyunsaturated fatty acids (derived from fish or corn oil respectively) on the secretion of very-low-density lipoprotein (VLDL) lipid and apolipoprotein B (apoB) by rat hepatocytes in culture was investigated. Remnants were prepared in vivo from chylomicrons obtained from rats given an oral dose of fish or corn oil and incubated with cultured hepatocytes for up to 16h. The medium was then removed and the secretion of cholesterol and triacylglycerol into the whole medium or the ρ < 1.050g/ml fraction during the following 7–24h was determined. After exposure of the cells to fish-oil as compared with corn-oil remnants, secretion of both cholesterol and triacylglycerol into the whole medium was decreased by 25–35%, and secretion into the ρ < 1.050g/ml fraction was decreased by 20–25%. In addition, the levels of apoB48 found in the ρ < 1.050g/ml fraction were significantly lower in cells treated with fish-oil rather than corn-oil remnants, although the levels of apoB100 remained unchanged. The expression of mRNA for apoB, as determined by reverse-transcriptase PCR, however, was not significantly changed after exposure of the cells to both types of remnants. These results demonstrate that the effects of dietary n-3 polyunsaturated fatty acids in depressing hepatic VLDL secretion occur directly when they are delivered to the liver from the intestine in chylomicron remnants, and that the secretion, but not the synthesis, of apoB is targeted.

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