The Role of the Small Intestine in the Disposal of Enzymes from Blood

Ga, Fleisher; Kg, Wakim

doi:10.1159/000458241

Cited by 9 publications

(5 citation statements)

References 4 publications

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“…Rotenone-insensitive NADH cytochrome c reductase activity was determined by the method of Dallner et al [26]. UDP-galactose: N-acetylglucosamine galactosyltransferase activity was determined by the method of Fleisher [27]. Glucose transport Glucose transport was assayed by measuring initial rates of 3-O-methylglucose influx.…”

Section: Fractionation Of Adipocytesmentioning

confidence: 99%

Biochemical and functional characterization of the rat liver glucose-transport system Comparisons with the adipocyte glucose-transport system

Ciaraldi¹,

Horuk²,

Matthaei³

1986

Biochemical Journal

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The properties of the glucose-transport systems in rat adipocytes and hepatocytes were compared in cells prepared from the same animals. Hormones and other agents which cause a large stimulation of 3-O-methylglucose transport in adipocytes were without acute effect in hepatocytes. Hepatocytes displayed a lower affinity for 3-O-methylglucose (20 mM) and alternative substrates than adipocytes (6 mM), whereas inhibitor affinities were similar in both cell types. The concentration and distribution of glucose transporters were determined by Scatchard analysis of D-glucose-inhibitable [3H]cytochalasin B binding to subcellular fractions. In liver, most of the transporters were located in the plasma membrane (42 +/- 5 pmol/mg of protein) with a small amount (4 +/- 3 pmol/mg) in the low-density microsomal fraction ('microsomes'), the reverse of the situation in adipocytes. Glucose transporters were covalently labelled with [3H]cytochalasin B by using the photochemical cross-linking agent hydroxysuccinimidyl-4-azidobenzoate and analysed by SDS/polyacrylamide-gel electrophoresis. A single D-glucose-inhibitable peak with a molecular mass of 40-50 kDa was seen in both plasma membrane and low-density microsomes. This peak was further characterized by isoelectric focusing and revealed a single peak of specific [3H]cytochalasin B binding at pI 6.05 in both low-density microsomes and plasma membrane, compared with peaks at pI 6.4 and 5.6 in adipocyte membranes. In summary: the glucose-transport system in hepatocytes has a lower affinity and higher capacity than that in adipocytes, and is also not accurately modulated by insulin; the subcellular distribution of glucose transporters in the liver suggests that few intracellular transporters would be available for translocation; the liver transporter has a molecular mass similar to that of the adipocyte transporter; the liver glucose transporter exists as a single charged form (pI 6.05), compared with the multiple forms in adipocytes. This difference in charge could reflect a functionally important difference in molecular structure between the two cell types.

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Section: Fractionation Of Adipocytesmentioning

confidence: 99%

Biochemical and functional characterization of the rat liver glucose-transport system Comparisons with the adipocyte glucose-transport system

Ciaraldi¹,

Horuk²,

Matthaei³

1986

Biochemical Journal

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“…Os indicadores bioquímicos CK e AST utilizados no presente estudo constituem marcadores de lesão muscular, dado o facto de serem proteínas que, quando libertadas para o espaço extracelular, em resposta ao exercício físico, permitem determinar, ainda que de forma indirecta, a existência de lesões [3,5]. As enzimas ALT e GGT encontram-se em maior concentração no fígado e epitélios dos ductos biliares e renais, respectivamente [18], o que pode sugerir a possibilidade de lesão hepática, quando observado um aumento significativo dos níveis séricos destas enzimas em resposta ao exercício físico [19].…”

Section: Discussionunclassified

Alterações agudas induzidas por uma prova de triathlon longo em diferentes biomarcadores enzimáticos e da função imune

Martins

Santos

2019

Rev Bras Fisiol Exerc

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Objectivo: Analisar as alterações hematológicas agudas induzidas por uma prova de triathlon longo. Avaliou-se o comportamento de diversos biomarcadores enzimáticos e da função imune em atletas portugueses masculinos de triathlon. Métodos: 10 atletas seniores masculinos (31,5 ± 1,2 anos; 69,3 ± 1,9 kg; 177,7 ± 1,4 cm; 22,0 ± 0,8 de IMC e 10,1 ± 2,2 % GC) divididos em grupos elite e não-elite. Foram recolhidas amostras de sangue venoso periférico antes e imediatamente após as provas. Utilizou-se estatística descritiva, testes não-paramétricos de Wilcoxon e Mann-Whitney e coeficiente de correlação de Spearman. Resultados: Verificou-se o aumento da actividade das enzimas CK e AST (p < 0,05) em ambos os grupos. O aumento da actividade da enzima GGT (p < 0,05) ocorreu somente no grupo elite. Foi constatado, em ambos os grupos, um aumento da contagem leucocitária, fundamentalmente expressa pelo aumento da contagem de neutrófilos (p < 0,05). Após a prova, registou-se a diminuição da relação CD4/CD8 e aumento das concentrações dos linfócitos T CD3+CD8+, T CD4+reg e T CD4+CD69+ nos atletas dos grupos não-elite. Conclusão: Os resultados encontrados sugerem que a intensidade e a duração da prova de triathlon condicionam as respostas dos diversos biomarcadores analisados em função do nível de treino dos atletas.Palavras-chave: triathlon, treino, actividade enzimática, sistema imune, linfócitos.

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“…This is indicated by the concentrations of radioactivity in the spleen and liver, comparable at 2 h and 8 h with that of the plasma, and the appreciable amounts in the tissue and lumen of the small intestine. Fleisher & Wakim (1968) demonstrated that the small intestine contributes to the clearance of injected alanine transaminase in the dog, and it is well established that the gastrointestinal tract plays a part in the elimination of plasma albumin (Armstrong, Margen & Tarver, 1960;Wetterfors, Gullberg, Liljedahl, Plantin, Birke & Olhagen, 1960;Ullberg, Birke, Ewaldsson, Hansson, Liljedahl, Plantin & Wetterfors, 1960;Glenert, Jamum & Riemer, 1962;Jeejeebhoy, Jarnum, Singh, Nadkarni & Westergaard, 1968;Skala, Vesely & Petrus, 1972).…”

Section: Discussionmentioning

confidence: 99%

The Fate of Circulating Lactate Dehydrogenase-5 in the Rabbit

Qureshi

Wilkinson

1976

Clinical Science

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1.In an attempt to determine the mechanism whereby enzymes are removed from the circulating plasma, purified rabbit-muscle lactate dehydrogenase-5 was labelled with lz5I and injected intravenously into rabbits. During the first hour after injection enzyme activity and radioactivity disappeared from the plasma at comparable fast rates, which are attributed mainly to distribution of the enzyme throughout the extracellular fluid. This was followed by a phase lasting about 7 h during which enzyme activity disappeared at a faster rate than the radioactivity, an observation indicating either intravascular breakdown of the enzyme protein or its degradation in the tissues, followed by release of labelled fragments into the circulation. Enzyme activity then reached a constant value and the plasma radioactivity continued to decrease at a slower exponential rate; it is suggested that this is due to removal of breakdown products.2. The radioactivity of the tissues was measured at various time-intervals after injection. After 2 h and 8 h highest concentrations were found in the spleen, liver, jejunum and duodenum. Relatively high concentrations were also found in the intestinal juices throughout the period of study, an observation which suggests that discharge via the small intestine is a major route whereby inactivated enzyme fragments are removed from the circulation.3. About 5% of the injected radioactivity was recovered in the faeces during the first 3 days, and the urine accounted for 73% during the same period. About 35 % of the urinary radioactivity was shown by silver nitrate precipitation and by chromatography to consist of free iodide and the remJnder appeared to consist of radio-iodinated amino acids or peptides. Free mono-and di-iodotyrosine were identified among the products. These results suggest that further breakdown in the intestine is followed by absorption of the products, which are excreted in the urine.

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The Role of the Small Intestine in the Disposal of Enzymes from Blood

Cited by 9 publications

References 4 publications

Biochemical and functional characterization of the rat liver glucose-transport system Comparisons with the adipocyte glucose-transport system

Biochemical and functional characterization of the rat liver glucose-transport system Comparisons with the adipocyte glucose-transport system

Alterações agudas induzidas por uma prova de triathlon longo em diferentes biomarcadores enzimáticos e da função imune

The Fate of Circulating Lactate Dehydrogenase-5 in the Rabbit

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