Glycerolphosphate acyltransferase, dihydroxyacetonephosphate acyltransferase and carnitine palmitoyltransferase in a glycogen storage disease (gsd/gsd) rat

Saggerson, E D; Topping, David L.

doi:10.1016/0014-5793(81)80443-7

Cited by 6 publications

(2 citation statements)

References 15 publications

(19 reference statements)

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“…In preliminary experiments (not shown) the same was found to hold for this activity in brown-adipocyte mitochondrial fractions. Because mitochondrial GPAT has very low activity with unsaturated acyl-CoA substrates, it has been found convenient to assay for microsomal GPAT in liver extracts with oleoyl-CoA as substrate, as well as assaying for NEM-sensitive activity with palmitoyl-CoA (Saggerson & Topping, 1981). The same was found to be true for brown adipocytes, in that 10 mM-NEM inhibited more than 9500 of GPAT activity measured with oleoyl-CoA in brown-adipocyte homogenates or in any subcellular fraction (results not shown).…”

Section: Resultsmentioning

confidence: 99%

Comparison of triacylglycerol synthesis in rat brown and white adipocytes. Effects of hypothyroidism and streptozotocin-diabetes on enzyme activities and metabolic fluxes

Baht

Saggerson

1988

Biochemical Journal

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1. Adipocytes were isolated from the interscapular brown fat and the epididymal white fat of normal, streptozotocin-diabetic and hypothyroid rats. 2. Measurements were made of the maximum rate of triacylglycerol synthesis by monitoring the incorporation of [U-14C]glucose into acylglycerol glycerol in the presence of palmitate (1 mM) and insulin (4 nM) and of the activities of the following triacylglycerol-synthesizing enzymes: fatty acyl-CoA synthetase (FAS), mitochondrial and microsomal forms of glycerolphosphate acyltransferase (GPAT), dihydroxyacetonephosphate acyltransferase (DHAPAT), monoacylglycerol phosphate acyltransferase (MGPAT), Mg2+-dependent phosphatidate phosphohydrolase (PPH) and diacylglycerol acyltransferase (DGAT). 3. FAS activity in brown adipocytes was predominantly localized in the mitochondrial fraction, whereas a microsomal localization of this enzyme predominated in white adipocytes. Subcellular distributions of the other enzyme activities in brown adipocytes were similar to those shown previously with white adipocytes [Saggerson, Carpenter, Cheng& Sooranna (1980) Biochem. J. 190, 183-189]. 4. Relative to cell DNA, brown adipocytes had lower activities of triacylglycerol-synthesizing enzymes and showed lower rates of metabolic flux into acylglycerols than did white adipocytes isolated from the same animals. 5. Diabetes decreased both metabolic flux into acylglycerols and the activities of triacylglycerol-synthesizing enzymes in white adipocytes. By contrast, although diabetes decreased metabolic flux into brown-adipocyte acylglycerols by 80%, there were no decreases in the activities of triacylglycerol-synthesizing enzymes, and the activity of PPH was significantly increased. 6. Hypothyroidism increased metabolic flux into acylglycerols in both cell types, and increased activities of all triacylglycerol-synthesizing enzymes in brown adipocytes. By contrast, in white adipocytes, although hypothyroidism increased the activities of FAS, microsomal GPAT and DGAT, this condition decreased the activities of mitochondrial GPAT and PPH. 7. It was calculated that the maximum capabilities for fatty acid oxidation and esterification are approximately equal in brown adipocytes. In white adipocytes esterification is predominant by approx. 100-fold. 8. Diabetes almost abolished incorporation of [U-14C]glucose into fatty acids in both adipocyte types. Hypothyroidism increased fatty acid synthesis in white and brown adipocytes by 50% and 1000% respectively.

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Section: Resultsmentioning

confidence: 99%

Comparison of triacylglycerol synthesis in rat brown and white adipocytes. Effects of hypothyroidism and streptozotocin-diabetes on enzyme activities and metabolic fluxes

Baht

Saggerson

1988

Biochemical Journal

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“…Laboratory findings in affected rats which have not been reported in the human patient include diminished hepatic lipogenesis and cholesterogenesis, a reduction in plasma triacylgtycerol and lactate levels, an altered plasma amino acid composition and an increased concentration of biliary acids . Changes in liver lipid metabolism are illustrated by diminished glycerolphosphate ac3~ltransferase and dihydroxyacetonephosphate acyltransferase activities and an increased carnitine palmitoyltransferase activity in liver tissue (Saggerson and Topping, 1981). Biochemical abnormalities could not be detected in heterozygous animals (Malthus et al, t980).…”

Section: Gsd VIIImentioning

confidence: 99%

Glycogen storage diseases in animals and their potential value as models of human disease

Walvoort

1982

J of Inher Metab Disea

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Glycogen storage diseases (GSD) are inborn errors of glycogen metabolism. Of the eight human GSD types in which the enzymatic deficiency has been identified, spontaneous animal counterparts have been reported for GSD I (glucose-6-phosphatase deficiency) in the mouse, for GSD II (acid alpha-glucosidase deficiency) in the dog, in cattle and in the quail, for GSD III (debrancher enzyme deficiency) in the dog and for GSD VIII (phosphorylase kinase deficiency) in the rat and the mouse. Experimentally induced GSD-like conditions have been described in the rat (Acarbose-induced GSD II-like conditions, iodoacetate-induced symptoms of myophosphorylase (GSD V) and myophosphofructokinase (GSD VII) deficiency) and the chicken (ochratoxin A-induced symptoms of cyclic AMP-dependent protein kinase deficiency). Enzymatic defects that are typical of the human GSD types have not been clearly identified in the induced animal conditions. The homology of animal and human GSD types is discussed. It is concluded that clinical, pathogenic and therapeutic studies of GSD may benefit from the use of animal models. For genetic studies of human GSD these models may prove to be of limited value, as the picture of several human GSD types is already obscured by genetic heterogeneity.

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The adaptive effects of dietary fish and safflower oil on lipid and lipoprotein metabolism in perfused rat liver

Wong

Nestel

Trimble

et al. 1984

Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metaboli

297

102

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Glycerolphosphate acyltransferase, dihydroxyacetonephosphate acyltransferase and carnitine palmitoyltransferase in a glycogen storage disease (gsd/gsd) rat

Cited by 6 publications

References 15 publications

Comparison of triacylglycerol synthesis in rat brown and white adipocytes. Effects of hypothyroidism and streptozotocin-diabetes on enzyme activities and metabolic fluxes

Comparison of triacylglycerol synthesis in rat brown and white adipocytes. Effects of hypothyroidism and streptozotocin-diabetes on enzyme activities and metabolic fluxes

Glycogen storage diseases in animals and their potential value as models of human disease

The adaptive effects of dietary fish and safflower oil on lipid and lipoprotein metabolism in perfused rat liver

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