Lipid biochemistry in the cold-acclimated rat

Portet, R

doi:10.1016/0305-0491(81)90002-x

Cited by 12 publications

(10 citation statements)

References 83 publications

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“…At variance, two authors showed that some increase occurred in caloric intake if comparing semipurified HL diet with stan dard grain ration (chow) [18] or with semipurified hypolipidic diet [8], Chronic expo sure to cold induces a constant rise in energy metabolism which in turn involves an in creased food intake. The hyperphagia that we observed in Osborne-Mendel rats at 5 °C (similar with NL and HL diet) is comparable with that in other strains [15].…”

Section: Discussionsupporting

confidence: 69%

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Effect of Environmental Temperature on Dietary Obesity in Osborne-Mendel Rats

Goubern¹,

Laury²,

Razanoelina³

et al. 1988

Ann Nutr Metab

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The effects of cold acclimation on cellularity, lipoprotein lipase (LPL) activity and lipolysis were studied in white adipose tissue of rats fed a high fat diet. Male Osborne-Mendel rats (7 weeks old) were exposed at either 28 or 5 °C for 10 weeks. The rats were fed a semipurified diet (normal fat (NL): 5% lard, high fat (HL): 54% lard) for the last 9 weeks. Caloric intake with NL and HL diets were comparable and cold exposure led to the same increase with both diets. At 28 °C, HL diet initiated both hypertrophy and hyperplasia; however, at 5 ° C only hyperplasia was observed. Total LPL activity showed high stimulation both in 28 and 5 °C HL rats. In vitro lipolytic stimulation by norepinephrine was lowered at 5 °C and abolished at 28 °C in HL-fed rats. HL diet resulted in enhanced lipid deposition without an increase in caloric intake. Even in cold-adapted Osborne-Mendel rats a relative obesity could be produced by a HL diet.

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Section: Discussionsupporting

confidence: 69%

“…Cold-exposed rats are hyperphagics and show a reduction in body weight gain [15]. Different stimuli may have differ ent effects on the development of the various fat deposits.…”

Section: Introductionmentioning

confidence: 99%

Effect of Environmental Temperature on Dietary Obesity in Osborne-Mendel Rats

Goubern¹,

Laury²,

Razanoelina³

et al. 1988

Ann Nutr Metab

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“…We have previously ob served a marked enhancement of potential lipogenic capacity in BAT of cold-adapted rats [6,13], In 9-week-old cold-adapted rats we do not support the suggestion that BAT is the major site (70%) for the conversion of carbohydrate into fat [11], In Long Evans rats, interscapu lar BAT represents around 30% of total BAT. Total synthesis in BAT was found to be only 70% at 03.00 and 40% at 15.00 h of total hepatic synthesis.…”

Section: Discussionmentioning

confidence: 67%

“…We have previously shown that cold expo sure has no effect on liver lipogenic enzyme activities [6,13], In one of these studies we observed that hepatic fatty acid synthesis doubles during the day but is halved at night. Therefore, it is likely that the mean daily hepatic lipogenesis is not modified by tem perature acclimation.…”

Section: Discussionmentioning

confidence: 98%

Modulation of Fatty Acid Synthesis in vivo in Brown Adipose Tissue, Liver and White Adipose Tissue of Cold-Acclimated Rats

Goubern¹,

Portet²

1986

Ann Nutr Metab

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The present experiment was an appraisal of the relative importance of fatty acid synthesis in brown adipose tissue (BAT) in young 28 or 5 °C adapted rats (9 weeks old). With a low-fat diet in vivo incorporation of ³H₂O into BAT fatty acids was 8 times lower during the day than during the night and was not modified by a 6-hour fast during the day (28 °C). Cold acclimation doubled (night) or increased 8 times (day) BAT lipogenesis. Fasting led to a halving of the diurnal rate. A high-fat diet led to large decrease in synthesis rate during the night but had a weak effect on diurnal synthesis. The specific activity of fatty acids was 3 times lower in phospholipids than in neutral lipids. A comparison between 9- and 15-week-old rats indicated that in older warm-adapted rats BAT lipogenesis decreased by half but that cold stimulation was unaltered. These results were compared with hepatic and epididymal white adipose tissue lipogenesis. In conclusion, we showed that BAT of 5 °C rats is an important but not the major site for the conversion of carbohydrate to fat and that the proportional involvement of each tissue is age-dependent.

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“…This is done by using most substrates available to fuel the heat-production pathways; as brown adipose tissue plays a key role in this process (Foster & Frydman, 1978), a large proportion of energetic substrates available would be oxidized by it. The chronic exposure or acclimation to low temperatures results in adaptive changes that prevent the excessive draining of valuable substrates for thermogenesis; the enlarged brown-adipose-tissue masses (Sundin & Cannon, 1980) have larger fat depots and are geared to use more energetic substrates obtained through increased food consumption (Portet, 1981).…”

Section: Introductionmentioning

confidence: 99%

Amino acid and glucose uptake by rat brown adipose tissue. Effect of cold-exposure and acclimation

López‐Soriano

López

Mampel

et al. 1988

Biochemical Journal

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The net uptake/release of glucose, lactate and amino acids from the bloodstream by the interscapular brown adipose tissue of control, cold-exposed and cold-acclimated rats was estimated by measurement of arteriovenous differences in their concentrations. In the control animals amino acids contributed little to the overall energetic needs of the tissue; glucose uptake was more than compensated by lactate efflux. Cold-exposure resulted in an enhancement of amino acid utilization and of glucose uptake, with high lactate efflux. There was a net glycine-and proline efflux-that partly compensated the positive nitrogen balance of the tissue; amino acids accounted for about one-third of the energy supplied by glucose to the tissue. Cold-acclimation resulted in a very high increase in glucose uptake, with a parallel decrease in lactate efflux and amino acid consumption. Branched-chain amino acids, however, were more actively utilized. This was related with a much higher alanine efflux, in addition to that of glycine and proline. It is suggested that most of the glucose used during cold-exposure is returned to the bloodstream as lactate under conditions of active lipid utilization, amino acids contributing their skeletons largely in anaplerotic pathways. On the other hand, cold-acclimation resulted in an important enhancement of glucose utilization, with lowered amino acid oxidation. Amino acids are thus used as metabolic substrates by the brown adipose tissue of rats under conditions of relatively scarce substrate availability, but mainly as anaplerotic substrates, in parallel to glucose. Cold-acclimation results in a shift of the main substrates used in thermogenesis from lipid to glucose, with a much lower need for amino acids.

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Lipid biochemistry in the cold-acclimated rat

Cited by 12 publications

References 83 publications

Effect of Environmental Temperature on Dietary Obesity in Osborne-Mendel Rats

Effect of Environmental Temperature on Dietary Obesity in Osborne-Mendel Rats

Modulation of Fatty Acid Synthesis in vivo in Brown Adipose Tissue, Liver and White Adipose Tissue of Cold-Acclimated Rats

Amino acid and glucose uptake by rat brown adipose tissue. Effect of cold-exposure and acclimation

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