Changes of Purine Metabolism During Differentiation of Rat Heart Myoblasts

Müller, Mathias M.; RumpoId, Helmut; Schopf, Gerhard; Zilla, Peter

doi:10.1007/978-1-4684-1248-2_74

Cited by 6 publications

(2 citation statements)

References 15 publications

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“…The activity of the nucleotide cycle was indeed demonstrated in the brain during depolarization by electroshock (Schultz and Lowenstein,1 978). A similar maturation-associated increase in the activity of AMP deaminase was found also in skeletal muscle (Zoref-Shani et al, 1983), cardiomyocyte cultures (Muller et al, 1986), and whole rat brain (Ogasawara et al, 1975). It remains to be seen whether the increase in AMP deaminase activity is common to a wide range of differentiating cells, or specific to those in which the activity of the adenine nucleotide cycle is of special functional importance.…”

Section: Discussionsupporting

confidence: 60%

Developmental Changes in the Activity of Enzymes of Purine Metabolism in Rat Neuronal Cells in Culture and in Whole Brain

Brosh

Sperling

Bromberg

et al. 1990

Journal of Neurochemistry

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The activities (Vmax) of several enzymes of purine nucleotide metabolism were assayed in premature and mature primary rat neuronal cultures and in whole rat brains. In the neuronal cultures, representing 90% pure neurons, maturation (up to 14 days in culture) resulted in an increase in the activities of guanine deaminase (guanase), purine-nucleoside phosphorylase (PNP), IMP 5'-nucleotidase, adenine phosphoribosyltransferase (APRT), and AMP deaminase, but in no change in the activities of hypoxanthine-guanine phosphoribosyltransferase (HGPRT), adenosine deaminase, adenosine kinase, and AMP 5'-nucleotidase. In whole brains in vivo, maturation (from 18 days of gestation to 14 days post partum) was associated with an increase in the activities of guanase, PNP, IMP 5'-nucleotidase, AMP deaminase, and HGPRT, a decrease in the activities of adenosine deaminase and IMP dehydrogenase, and no change in the activities of APRT, AMP 5'-nucleotidase, and adenosine kinase. The profound changes in purine metabolism, which occur with maturation of the neuronal cells in primary cultures in vitro and in whole brains in vivo, create an advantage for AMP degradation by deamination, rather than by dephosphorylation, and for guanine degradation to xanthine over its reutilization for synthesis of GMP. The physiological meaning of the maturational increase in these two ammonia-producing enzymes in the brain is not yet clear. The striking similarity in the alterations of enzyme activities in the two systems indicates that the primary culture system may serve as an appropriate model for the study of purine metabolism in brain.

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Section: Discussionsupporting

confidence: 60%

Developmental Changes in the Activity of Enzymes of Purine Metabolism in Rat Neuronal Cells in Culture and in Whole Brain

Brosh

Sperling

Bromberg

et al. 1990

Journal of Neurochemistry

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“…The very marked age-related increase in the activity of AMP deaminase, demonstrated in the astroglia, is similar to that found before in skeletal muscle 50 and in cardiomyocyte cultures. 34 The reaction catalyzed by AMP deaminase is the rate-limiting step in the operation of the purine nucleotide cycle (AMP ---, IMP ---, adenylosuccinic acid ---, AMP). 40 This cycle has a major role in the maintenance of the normal energy charge in the cell, as well as in the preservation of cellular purine nucleotide content.…”

Section: Purine Nucleotide Synthesismentioning

confidence: 99%

Developmental changes in purine nucleotide metabolism in cultured rat astroglia

Zoref-Shani

Bromberg

Lilling

et al. 1995

Intl J of Devlp Neuroscience

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The present study was conducted in order to clarify the role of the glia in brain purine metabolism. This, in connection with the clarification of the etiology of the neurological manifestations associated with some of the inborn errors of purine metabolism in man. Purine nucleotide content, the capacity for de novo and salvage purine synthesis and the activity of several enzymes of purine nucleotide degradation, were assayed in primary cultures of rat astroglia in relation to culture age. The capacity of the intact cells to produce purine nucleotides de novo exhibited a marked decrease with the culture age, but the activity of hypoxanthine-guanine phosphoribosyltransferase (HGPRT), catalyzing salvage nucleotide synthesis, increased. Aging was also associated with a marked increase in the activity of the degradation enzymes AMP deaminase, purine nucleoside phosphorylase (PNP) and guanine deaminase (guanase). The activity of adenosine deaminase and of AMP-5'-nucleotidase, increased markedly during the first 17 days in culture, but decreased thereafter. The results indicate that purine nucleotide metabolism in the cultured astroglia is changing with aging to allow the cells to maintain their nucleotide pool by reutilization of preformed hypoxanthine, rather than by de-novo production of new purines. Aging is also associated with increased capacity for operation of the adenine nucleotide cycle, contributing to the homeostasis of adenine nucleotides and to the energy charge of the cells. In principle, the age-related alterations in purine metabolism in the astroglia resemble those occurring in the maturating neurons, except for the capacity to produce purines de novo, which exhibited inverse trends in the two tissues. However, in comparison to the neurons, the cultured astroglia possess the capacity for a more intensive metabolism of purine nucleotides.

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On the Role of Myocardial AMP-Deaminase

Składanowski

1988

Developments in Cardiovascular Medicine

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Changes of Purine Metabolism During Differentiation of Rat Heart Myoblasts

Cited by 6 publications

References 15 publications

Developmental Changes in the Activity of Enzymes of Purine Metabolism in Rat Neuronal Cells in Culture and in Whole Brain

Developmental Changes in the Activity of Enzymes of Purine Metabolism in Rat Neuronal Cells in Culture and in Whole Brain

Developmental changes in purine nucleotide metabolism in cultured rat astroglia

On the Role of Myocardial AMP-Deaminase

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