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Journal ArticleDOI

Acute effects of insulin on fatty acid metabolism in isolated rat hepatocytes.

01 Sep 1980-Hormone and Metabolic Research (Horm Metab Res)-Vol. 12, Iss: 9, pp 425-430
TL;DR: Evidence is presented that malonyl-CoA plays an important role in the insulin-mediated control of both ketogenesis and de novo fatty acid synthesis and all metabolic parameters studied are affected by glucagon in a manner opposite to that of insulin.
Abstract: Isolated rat hepatocytes, previously shown to display enhanced rates of fatty acid biosynthesis upon a brief exposure to insulin, were used to study acute effects of this hormone on other aspects of hepatic fatty acid metabolism. Insulin activates the incorporation of exogenously added fatty acids into glycerolipids and depresses their utilization in the formation of ketone bodies. Insulin increases both the activity of acetyl-CoA carboxylase and the cellular content of malonyl-CoA. Evidence is presented that malonyl-CoA plays an important role in the insulin-mediated control of both ketogenesis and de novo fatty acid synthesis. All metabolic parameters studied are affected by glucagon in a manner opposite to that of insulin.
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Journal ArticleDOI
TL;DR: The results suggest that oligofructose decreases lipogenic enzyme gene expression, which could explain, at least partially, the metabolic effect of oligof fructose.

212 citations

Journal ArticleDOI
TL;DR: It is suggested that OFS decreases serum triacylglycerols by reducing de nova fatty acid synthesis in the liver; the lower insulin level in the serum of OFS-fed rats could explain, at least partly, the metabolic effect induced by such nondigestible carbohydrates.
Abstract: Dietary supplementation with oligofructose (OFS; 100 g/kg), a non-digestible oligomer of beta-D-fructose, decreases serum triacylglycerols in serum and VLDL of rats. In order to investigate the role of hepatic metabolism in the hypolipidaemic effect of OFS, male Wistar rats were fed on a standard diet with or without 100 g Raftilose P95/kg as OFS source for 30 d. OFS feeding (1) significantly decreased triacylglycerol and phospholipid concentrations in both blood and liver, (2) increased the glycerol-3-phosphate liver content but decreased the hepatic activity of glycerol-3-phosphate acyltransferase (EC 2.3.1.15), suggesting a decrease in acylglycerol synthesis, (3) did not affect the blood non-esterified fatty acid concentrations, but (4) reduced by 54% the capacity of isolated hepatocytes to synthesize and secrete triacylglycerols from labelled acetate; the activity of fatty acid synthase, a key lipogenic enzyme was also significantly decreased. These findings suggest that OFS decreases serum triacylglycerols by reducing de novo fatty acid synthesis in the liver; the lower insulin level in the serum of OFS-fed rats could explain, at least partly, the metabolic effect induced by such non-digestible carbohydrates.

188 citations

Journal ArticleDOI
TL;DR: Evidence supporting the involvement of two recently recognized factors linking obesity with neurodegeneration: the induction of pro-inflammatory cytokines and onset of insulin and insulin-like growth factor 1 (IGF-1) resistance is reviewed.

162 citations


Cites background from "Acute effects of insulin on fatty a..."

  • ...In addition to its effects on glucose metabolism, insulin down-regulates gluconeogenesis, increases glycogen synthesis, increases adiposity, promotes lipid synthesis, and inhibits lipolysis and fatty acid esterification (Wagle et al., 1975; Beynen et al., 1980; Baskin et al., 1999)....

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Journal ArticleDOI
01 Dec 1980-Diabetes
TL;DR: The ability to keep large amounts of triacylglycerols on board would not be useful, however, if it were not possible to quickly and efficiently stop diverting foodstuffs into triacyglycerol formation and to start utilizing these compounds to provide the energy necessary to synthesize ATP as mentioned in this paper.
Abstract: Lipids are essential components of all living cells, functioning as an energy store and playing an important role in all biologic membranes. Triacylglycerols, the storage form and most abundant of the glycerolipids, represent a highly concentrated form of energy, yielding twice as many calories per gram as carbohydrate or protein. The phospholipids are amphipathic compounds which, along with cholesterol, are found in membranes where they interact to provide a polar-faced, hydrophobic continuum of critical importance for proper cell structure and function. A major function of lipogenesis is to store (as triacylglycerols) the chemical energy or foodstuffs ingested above the immediate requirements of an organism. Contrary to protein, which is not stored, and to carbohydrate, which can only be stored in limited quantities, the capacity to store triacylglycerols is almost unlimited. The ability to keep large amounts of triacylglycerols on board would not be useful, however, if it were not possible to quickly and efficiently stop diverting foodstuffs into triacylglycerol formation and to quickly and efficiently start utilizing these compounds to provide the energy necessary to synthesize ATP. For this reason, mechanisms have evolved which finely tune the synthesis and degradation of triacylglycerol to the ever changing demand for ATP. In contrast, phospholipid and cholesterol synthesis must be, at least, partially maintained (or their degradation curtailed), even in the face of limited food intake or frank starvation, to provide sufficient quantities of these lipids to fulfill their crucial role in biologic membranes. In rodents the proportion of total body fatty acids synthesized by the liver ranges from 3% (fasted animals) to 50%

144 citations