Eine neue Bestimmung der Neutralfette im Blutserum und Gewebe

Eggstein, M.

doi:10.1007/bf01747717

Cited by 249 publications

(63 citation statements)

References 16 publications

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“…An enzymic method was used for plasma triglyceride determination (Eggstein, 1966) and serum calcium was measured on a Vickers analyser (Vickers Medical Engineering, Basingstoke, Hants). Faecal bile acids and neutral steroids were measured by gas-liquid chromatography using the method of Evrard & Janssen (1968) as modified by Mitchell, Findlay, Prescott, Eastwood & Horn (1973).…”

Section: Analysesmentioning

confidence: 99%

The effect of wheat fibre on plasma lipids and faecal steroid excretion in man

Kay

1977

Br J Nutr

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I. The effect of isoenergetic substitution of bran and wholemeal bread for white flour and white bread was investigated in six healthy volunteers in a metabolic unit. 2.A 21 d high-fibre experimental period was preceded and followed by a 14 d control period, so that each experiment lasted 7 weeks. Blood samples were taken on each of the last 3 d and faeces collected (using carmine markers) for the last 6 d of each diet period.3. Plasma cholesterol, triglycerides and serum calcium concentrations were not altered by the addition of wheat fibre.4. Wheat fibre caused a significant increase in faecal bulk and frequency. Faecal steroid excretion was the same in the last week of the first control and the high-fibre periods but increased in the subsequent control period.

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Section: Analysesmentioning

confidence: 99%

The effect of wheat fibre on plasma lipids and faecal steroid excretion in man

Kay

1977

Br J Nutr

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“…However, the maximal rate of its cleavage being low x min-l x mg protein-l) [25], relatively high concentrations of tissue preparations (20 -50 O/,, homogenate) [4,7] have to be used to obtain measurable activities. This difficulty has not been overcome by recent, more sensitive methods for the estimation of free fatty acids or glycerol [22,26]. According to the experiments of Khoo et al [ l l ] exogenous triolein is hydrolyzed only by a portion of the lipases which are not actually bound to endogenous glycerides in the tissue preparation.…”

Section: Discussionmentioning

confidence: 99%

“…Since the concentrations of enzyme preparations were high, their blanks without added substrate represented about 25O/, of noncorrected values. Glycerol was estimated in the aliquots of 0.5 ml enzymatically [22].…”

Section: I P E Assaymentioning

confidence: 99%

Heterogeneity of Triglyceride Lipase of Rat Adipocytes

Chmelařová

Chmelař

1974

European Journal of Biochemistry

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1.Triglyceride and monoglyceride lipase activities were compared in different preparations from rat adipose tissue or isolated adipocytes: fat-free homogenate, 105000 x g fat-free infranatant (soluble fraction) and 105000 x g sediment (particulate fraction) were assayed. The ratio of monoolein to triolein cleavage was 6.8 in whole homogenate and 1.9 and 20 in particulate and soluble fractions, respectively. Lipoprotein lipase activity of these enzyme preparations was not measurable under the experimental conditions used.2. Since specific activities especially of triglyceride lipase(s) were low, other substrates were tested to increase the sensitivity. Among them 2-naphthol laurate was found to be hydrolyzed by the whole homogenate at a rate about 50 times higher than triolein.3. 2-Naphthol laurate was readily hydrolyzed by lipases in all preparations studied. Dioxane and ethylene glycol, the typical inhibitors of monoglyceride lipase activity strongly inhibited its cleavage in the soluble fraction whereas the typical inhibitors of triglyceride lipase activity (Triton X-100, lanthanum nitrate, 2-propanol) were effective in inhibiting 2-naphthol laurate cleavage particularly in 105000 x g sediment. 4.Heat inactivation, pH optima and starch-block electrophoresis confirmed the difference between lipases in particulate and soluble fractions. Whereas in the soluble fraction these criteria did not reveal further heterogeneity, the particulate fraction was apparently heterogenous and exhibited two pH optima at 6.5 and 8, a non-linear rate of heat inactivation with time and two electrophoretic fractions, thus suggesting the presence of two distinct triglyceride lipases.5. The monoglyceride lipase character of the soluble lipase is supported by the kinetic evidence of competition between monoolein and 2-naphthol laurate. The particulate lipases, on the other hand, exhibited competitive inhibition of 2-naphthol laurate cleavage by triolein, which supports their triglyceride lipase character.6. 2-Naphthol laurate might be thus a valuable tool in the study of both monoglyceride and triglyceride lipase activities in adipose tissue. The possibility of high dilution of enzyme preparation excludes the interference of endogenous substrate, the preparation of a stable substrate emulsion is easy and the estimation of the first product of the reaction is rapid and simple.Among a number of lipases present in adipose tissue and responsible for splitting glycerides stored in adipocytes, intracellular hormone-sensitive triglyceride lipase represents the limiting step of lipolysis. Although the early studies of Rizack [1,2] and further results of other authors [3--81, especially the recent work from Steinberg's laboratory [9-111 accumulated an important body of information concerning this enzyme, its characterization is still incomplete. The principle obstacles to the study of triglyceride lipase in cell-free preparations are its low activity, instability and overlapping substrateEnzymes. Esterases, carboxylic-ester hydrolases (EC 3.1.1....

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“…These samples were used to measure the blood glucose concentrations by the method of Werner et al (1970) Elphick (1975). Free glycerol and triacylglycerol concentrations in the blood were measured by the method of Eggstein (1966).…”

Section: Induction Ofexperimental Diabetesmentioning

confidence: 99%

The effect of chronic diabetes, induced by streptozotocin, on the activities of some enzymes of glycerolipid synthesis in rat liver

1978

Biochemical Journal

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1. Rats were injected with a single dose of 35mg of streptozotocin/kg body wt. They exhibited a diabetes that was characterized by glycosuria, polyuria, polydipsia, hyperphagia, hyperglycaemia, increased concentrations of unesterified fatty acids, glycerol and triacylglycerols in the serum and an increased activity of glucose 6-phosphatase in the liver. 2. After 10 weeks the hepatic activities of the microsomal glycerol phosphate acyltransferase, phosphatidate phosphohydrolase, phosphatidate cytidylyltransferase, diacylglycerol acyltransferase, choline phosphotransferase, CDP-diacylglycerol-inositol phosphatidyltransferase and the soluble phosphatidate phosphohydrolase were measured. 3. The only significant changes were an increase in the activity of the soluble phosphatidate phosphohydrolase and a decrease in that of the CDP-diacylglycerolinositol phosphatidyltransferase in the diabetic rats. 4. These results are discussed in relation to the control of glycerolipid synthesis.Diabetes mellitus is characterized by hyperglycaemia, which is often accompanied by glycosuria, and by an increase in the consumption of food and water and in urine output. In severe cases there is ketonaemia, ketonuria and hypertriglyceridaemia. The last is usually caused by an accelerated secretion of very-low-density lipoprotein, and the severity of the hypertriglyceridaemia can be taken as an indication of the adequacy of the control of the diabetes (Nikkila & Kekki, 1973;Nikkila, 1974).In the present study rats were made chronically diabetic by a single injection of streptozotocin. These animals were then used to investigate whether the diabetic state is accompanied by changes in the relative activities of the enzymes responsible for the synthesis ofglycerolipids in the liver. It is hoped that these results will add to our understanding of how glycerolipid synthesis is controlled.

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Eine neue Bestimmung der Neutralfette im Blutserum und Gewebe

Cited by 249 publications

References 16 publications

The effect of wheat fibre on plasma lipids and faecal steroid excretion in man

The effect of wheat fibre on plasma lipids and faecal steroid excretion in man

Heterogeneity of Triglyceride Lipase of Rat Adipocytes

The effect of chronic diabetes, induced by streptozotocin, on the activities of some enzymes of glycerolipid synthesis in rat liver

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