QUANTITATIVE ASPECTS OF GLUTAMATE UTILIZATION BY RAT ADIPOSE TISSUE AND LIVER IN VITRO: EFFECT OF PERIODICITY OF EATING

1966 ◽  
Vol 44 (2) ◽  
pp. 275-285 ◽  
Author(s):  
Gilbert A. Leveille ◽  
Richard W. Hanson
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Krebs Cycle ◽  
Acid Synthesis ◽  
Meal Feeding ◽  
Rat Adipose Tissue ◽  
Relative Differences ◽  
Vitro Effect

The activity of two pathways supplying substrate for lipogenesis was enhanced in adipose tissue of meal-fed rats. One of these pathways, the forward pathway, involves the entry of α-ketoglutarate into the mitochondria, and metabolism via the Krebs cycle; the second pathway involves the backward flow of α-ketoglutarate to citrate in the cytoplasm, and cleavage of citrate to supply acetyl-CoA. Meal feeding increased fatty acid synthesis via the forward and backward pathways, but the relative amount of glutamate incorporated into lipid via the backward pathway decreased as a result of meal eating. The relative importance of the backward and forward pathways to the incorporation of α-ketoglutarate into fatty acid appeared to be similar for liver and adipose tissue. Lipogenesis from glutamate was significantly greater in adipose tissue incubated in bicarbonate than in phosphate buffer; however, the relative differences between tissues from meal-fed rats and from those fed ad libitum were similar in the two buffers. The possible importance of the backward pathway in the supply of precursors for fatty acid synthesis is discussed.

scholarly journals Effects of Prolactin in Vitro on Fatty Acid Synthesis in Rat Adipose Tissue

1959 ◽  
Vol 234 (12) ◽  
pp. 3111-3114 ◽  
Author(s):  
Albert I. Winegrad ◽  
Walter N. Shaw ◽  
Francis D.W. Lukens ◽  
William C. Stadie
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Rat Adipose Tissue

Effect of the entero-pancreatic hormones, gastric inhibitory polypeptide and glucagon-like polypeptide-1(7–36) amide, on fatty acid synthesis in explants of rat adipose tissue

1991 ◽  
Vol 130 (2) ◽  
pp. 267-272 ◽  
Author(s):  
J. Oben ◽  
L. Morgan ◽  
J. Fletcher ◽  
V. Marks
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Gastric Inhibitory Polypeptide ◽  
Acid Synthesis ◽  
Acetate Incorporation ◽  
Omental Adipose Tissue ◽  
Wet Weight ◽  
Glucagon Like Peptide ◽  
Rat Adipose Tissue

ABSTRACT The effect of gastric inhibitory polypeptide (GIP), glucagon-like peptide-1(7–36) amide, (GLP-1(7–36) amide), glucagon-like peptide-2 (GLP-2), glucagon and insulin on fatty acid synthesis in explants of rat adipose tissue from various sites was investigated. GIP, GLP-1(7–36) amide and insulin stimulated fatty acid synthesis, as determined by measuring the incorporation of [14C]acetate into saponifiable fat, in a dose-dependent manner, over the concentration range 5–15 ng/ml (0·87–2·61 nmol/l) for insulin and 0·5–7·5 ng/ml for GIP (0·10–1·50 nmol/l) and GLP-1(7–36) amide (0·15–2·27 nmol/l). Insulin and GIP caused a significantly greater stimulation of [14C]acetate incorporation into fatty acids in omental adipose tissue than in either epididymal or subcutaneous adipose tissue. Both GIP and GLP-1(7–36) amide had the ability to stimulate fatty acid synthesis within the physiological range of the circulating hormones. At lower concentrations of the hormones, GLP-1(7–36) amide was a more potent stimulator of fatty acid synthesis than GIP in omental adipose tissue culture; the basal rate of fatty acid synthesis was 0·41±0·03 pmol acetate incorporated/mg wet weight tissue per 2 h; at 0·10 nmol hormone/l 1·15±0·10 and 3·40±0·12 pmol acetate incorporated/mg wet weight tissue per 2 h for GIP and GLP-1(7–36) amide respectively (P < 0·01). GLP-2 and glucagon were without effect on fatty acid synthesis in omental adipose tissue. The study indicates that GIP and GLP-1(7–36) amide, in addition to stimulating insulin secretion, may play a direct physiological role in vivo, in common with insulin, in promoting fatty acid synthesis in adipose tissue. Journal of Endocrinology (1991) 130, 267–272

scholarly journals Aspects of adipose-tissue metabolism in foetal lambs

1981 ◽  
Vol 196 (3) ◽  
pp. 819-824 ◽  
Author(s):  
R G Vernon ◽  
J P Robertson ◽  
R A Clegg ◽  
D J Flint
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Lipoprotein Lipase ◽  
Fatty Acid Synthesis ◽  
Fatty Acid Synthetase ◽  
Acid Synthesis ◽  
Acetyl Coa ◽  
Perirenal Adipose Tissue ◽  
Glycerol Synthesis

1. The mean volume of adipocytes, the rates of fatty acid and acylglycerol glycerol synthesis from various precursors (in vitro), the rates of oxidation of acetate and glucose (in vitro) and the activities of lipoprotein lipase and various lipogenic enzymes were determined for perirenal adipose tissue from foetal lambs during the last month of gestation. 2. The fall in the rate of growth of perirenal adipose tissue during the last month of gestation is associated with a diminished capacity for fatty acid synthesis and lipoprotein lipase activity, but no change in the rate of acylglycerol glycerol synthesis was observed. There was no fall in the activities of cytosolic acetyl-CoA synthetase or the NADP-linked dehydrogenases, suggesting that the decrease in the rate of fatty acid synthesis was due to an impairment at the level of acetyl-CoA carboxylase or fatty acid synthetase. 3. The rate of fatty acid synthesis from acetate was greater than that from glucose. The rate of fatty acid synthesis from glucose per adipocyte of foetal lambs was similar to that of young sheep. The characteristic metabolism of adipose tissue of the adult sheep is thus present in the foetus, despite the relatively large amounts of glucose in the foetal ‘diet’.

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